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Exercise improves health and physical function in older people, but very few older people participate although the trend is for increasing participation. This study sought to determine whether short duration sprint interval training (SIT) improves health and physical function in older people. Seventeen (9 M and 8 F) older adults (age 66 ± 3 years) were recruited. Participants had blood pressure, physical function and blood lipid profile measured and were then allocated to a control group (CON n = 7) or a SIT group (n = 10). The control group maintained daily activities; the SIT group performed 10 weeks of twice-weekly training sessions of 6-s sprints. By week 10, training sessions lasted 11.6 ± 0.6-min. Ten weeks of SIT resulted in significant changes in pulse pressure (CONpre 59 ± 18 mmHg; CONpost 60 ± 9 mmHg; SITpre 56 ± 14 mmHg; SITpost 49 ± 7 mmHg; p = 0.007), mean blood pressure (CONpre 100 ± 10 mmHg; CONpost 97 ± 11 mmHg; SITpre 102 ± 7 mmHg; SITpost 93 ± 8 mmHg; p = 0.003), timed get up and go (CONpre 6.9 ± 1.1 s; CONpost 6.9 ± 1.0 s; SITpre 7.4 ± 1.2 s; SITpost 6.6 ± 1.0 s; p = 0.005), loaded 50 m walk (CONpre 6.9 ± 1.1 s; CONpost 6.9 ± 1.0 s; SITpre 7.4 ± 1.2 s; SITpost 6.6 ± 1.0 s; p = 0.005),and total cholesterol: HDL cholesterol ratio (CONpre 4.2 ± 0.7; CONpost 4.0 ± 0.7; SITpre 4.4 ± 1.1; SITpost 3.2 ± 0.7; p = 0.01). SIT is an effective way to maintain blood pressure, lipid profile, and physical function during aging and is an effective tool for promoting optimal aging.
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Sport Sciences for Health (2019) 15:123–131
Extremely shortduration sprint interval training improves vascular
health inolder adults
SimonAdamson1· MykolasKavaliauskas2· TakakiYamagishi1· ShaunPhillips3· RossLorimer1· JohnBabraj1
Received: 18 December 2017 / Accepted: 1 September 2018 / Published online: 14 September 2018
© The Author(s) 2018
Exercise improves health and physical function in older people, but very few older people participate although the trend is
for increasing participation. This study sought to determine whether short duration sprint interval training (SIT) improves
health and physical function in older people. Seventeen (9 M and 8 F) older adults (age 66 ± 3years) were recruited. Par-
ticipants had blood pressure, physical function and blood lipid profile measured and were then allocated to a control group
(CON n = 7) or a SIT group (n = 10). The control group maintained daily activities; the SIT group performed 10weeks of
twice-weekly training sessions of 6-s sprints. By week 10, training sessions lasted 11.6 ± 0.6-min. Ten weeks of SIT resulted
in significant changes in pulse pressure (CONpre 59 ± 18mmHg; CONpost 60 ± 9mmHg; SITpre 56 ± 14mmHg; SITpost
49 ± 7mmHg; p = 0.007), mean blood pressure (CONpre 100 ± 10mmHg; CONpost 97 ± 11mmHg; SITpre 102 ± 7mmHg;
SITpost 93 ± 8mmHg; p = 0.003), timed get up and go (CONpre 6.9 ± 1.1s; CONpost 6.9 ± 1.0s; SITpre 7.4 ± 1.2s; SITpost
6.6 ± 1.0s; p = 0.005), loaded 50m walk (CONpre 6.9 ± 1.1s; CONpost 6.9 ± 1.0s; SITpre 7.4 ± 1.2s; SITpost 6.6 ± 1.0s;
p = 0.005),and total cholesterol: HDL cholesterol ratio (CONpre 4.2 ± 0.7; CONpost 4.0 ± 0.7; SITpre 4.4 ± 1.1; SITpost
3.2 ± 0.7; p = 0.01). SIT is an effective way to maintain blood pressure, lipid profile, and physical function during aging and
is an effective tool for promoting optimal aging.
Keywords Aging· Sprint interval training· Blood pressure· Physical function
Aging is associated with a reduction in cardiac and arterial
function with a marked increase in arterial stiffness, result-
ing in isolated systolic hypertension [1]. Pulse pressure is a
surrogate pulsatile component of blood pressure made up of
ventricular ejection, arterial stiffness and wave reflection [2].
At rest, ventricular ejection does not change over the lifespan
[3] and following 12months of endurance exercise ventricu-
lar ejection does not change at rest [4]. Therefore, it is sug-
gested that at rest pulse pressure represents either arterial
stiffness or wave reflection in older adults [2]. Furthermore,
arterial stiffening is a predictor for a number of vascular
diseases including heart failure, stroke and dementia [5].
Arterial stiffening is a predictor of vascular disease, but is
also strongly associated with the loss of physical function
and onset of functional limitations of old age [6].
The development of arterial stiffness has been linked to
both abnormal lipid and glucose metabolism [7]. However,
with age there is a decrease in glucose tolerance, result-
ing in increased fasting and post-prandial blood glucose
levels across the lifespan [8]. In addition, circulating total
cholesterol, low-density lipoprotein (LDL) cholesterol and
triglycerides concentrations can be elevated with age [9]
and are strongly associated with cardiovascular disease
risk [10]. Higher total cholesterol: high density lipopro-
tein (HDL) cholesterol ratios have been reported in older
adults with atherosclerotic alterations compared to those
with no atherosclerotic alterations [11]. The mechanisms
linking lipid profile to arterial stiffness are multifactorial,
including atherosclerosis, changes in the elastic elements
of the arterial wall, endothelial dysfunction and inflamma-
tion [12]. Following 12weeks of an aerobic and resistance
* John Babraj
1 Division ofSport andExercise Science, Abertay University,
DundeeDD11HG, Scotland,UK
2 School ofApplied Sciences, Sport, Exercise andHealth
Sciences, Edinburgh Napier University, Edinburgh, UK
3 Division ofSport andExercise Science, Edinburgh
University, Edinburgh, UK
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124 Sport Sciences for Health (2019) 15:123–131
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exercise programme there is an improvement in systolic
blood pressure, pulse wave velocity and a reduction in
lipid profile in obese women [13]. Likewise, a 5-week
aerobic exercise programme has been shown to decrease
circulating triglycerides and glycosylated heamoglobin
(HbA1c) in older men [14]. Despite the benefits of aero-
bic and resistance exercise, the majority of older adults do
not take part in traditional exercise with time, dislike of
these exercise modes and risk of injury being barriers to
exercise participation [15].
Sprint interval training (SIT) can be a time-efficient
exercise paradigm but duration of SIT protocols can vary
between 10-min [16] and 30-min [17] depending on sprint
duration and recovery. Longer SIT protocols have typically
utilised 4–6 × 30-s sprints in a 1:8 work to rest interval on
3days per week and produce similar adaptations to tradi-
tional endurance training [18]. However, these protocols
last close to 30min. To overcome this number of recent
studies have looked at utilising 10-min protocols using
fewer sprints but still requiring a minimum of 3 training
days per week. Metcalfe etal. [19] demonstrated improved
VO2 max (13%) and insulin sensitivity (28%) in young
males when carrying out 2 × 20-s sprints. Gillen etal. [20]
demonstrate similar improvements in VO2 max (12%) in
young adults when using 3 × 20-s sprints at a lower resist-
ance and an 8% reduction in mean arterial pressure after
6weeks of training. Despite this reduction in total time,
the use of 20-s sprints may not be appropriate for older
adults due to the extended cardiovascular load, which is
similar to 30-s sprints in young adults [21]. Further, these
studies still require training to be carried out on 3days of
the week, which may limit people’s ability to follow these
protocols. In a middle-aged population, twice weekly SIT
sessions consisting of 6–10 × 6-s sprints, with a maximum
training duration of 10-min, has been shown to increase
VO2 peak (8%), decrease blood glucose area under the
curve (6%) and improve physical function [16]. Recently,
it has been demonstrated that a progressive SIT protocol
performed twice weekly over 6weeks will also improve
physical function and blood glucose control in older adults
[22]. However, the effectiveness of short sprints on blood
pressure components has not been investigated.
Longer duration sprints have been shown to improve
cardiovascular function and lower blood pressure in young
adults [18]. However, shorter duration sprints have been
shown to improve physical function and glucose metabo-
lism in older adults [22]. Therefore, the aim of this study
was to determine the effectiveness of a 10-week extremely
short duration SIT protocol (6-s) on blood pressure and
health in an older adult population. It was hypothesized
that SIT group would have improvements in physical func-
tion and resting blood pressure.
Materials andmethods
17 older adults (age range 60–71years) were recruited for
the study via local newspaper advertisement and were allo-
cated using a stratified approach to ensure that baseline age
was similar in the control group (CON: three males and
four females; Table1) or a twice per week SIT group (SIT:
four females, six males; Table1). More participants were
recruited to the SIT group to allow for potential dropout,
although dropout rate was zero. All participants were inac-
tive and participants were excluded if they had any metabolic
disease or cardiovascular disease. All participants had well-
controlled hypertension (blood pressure 160/90mmHg)
and were taking oral hypertensive medication which
remained unchanged for 6months prior to and during the
study. There was no significant difference in baseline char-
acteristics of the two groups (Table1), therefore, differences
in the group sizes do not bias the result [23]. Participants
allocated to the control group were asked to maintain their
normal lifestyle throughout the study period but took part
in no structured training. Participants allocated to the SIT
group took part in a twice weekly, 10-week SIT intervention,
but no other exercise training. All participants were asked
to report any changes in lifestyle or medication during the
study. All participants provided verbal and written informed
consent. The study had ethical approval from Abertay Uni-
versity Ethics Committee (SHS0701615) and conducted in
accordance with the declaration of Helsinki.
Baseline testing
Participant reported to the laboratory having fasted over-
night and height was recorded using a SECA 217 Stadi-
ometer (SECA United Kingdom, Birmingham, UK) and
weight determined using a SECA Medical 780 weighing
scales (SECA United Kingdom, Birmingham, UK).
Blood pressure
Prior to obtaining blood pressure measurements, all partici-
pants sat quietly for 5min with both arms in a forward posi-
tion, on a flat table surface. Blood pressure, pulse pressure
and mean arterial pressure was measured using a WatchBP
Office ABI Automatic Office Blood Pressure Measurement
Device (Microlife WatchBP AG, Widnau, Switzerland).
Triplicate blood pressure measurements were made, with a
1-min interval in-between, and the average value for blood
pressure, pulse pressure (pulse pressure = systolic − diastolic
pressure) and mean arterial pressure was recorded for both
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125Sport Sciences for Health (2019) 15:123–131
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left and right arms. It has been suggested that differences
in right and left arm blood pressure provides evidence of
peripheral vascular disease and is of clinical importance
Lipid profile
A finger prick blood sample was taken to allow measurement
of lipid profile. The initial blood droplet was discarded and
the second blood droplet taken for analysis of fasting lipid
levels (CardioChek PA, Polymer Technology Systems Inc,
Indianapolis, USA, within run CV for total cholesterol 4.7%,
HDL cholesterol 5.9% and triglyceride 4.3%). LDL choles-
terol was calculated using the modified Friedewald calcu-
lation (LDL-C (mgdl−1) = non-HDL-C × 90% − TG × 10%;
where TG = triglyceride, non-HDL-C = total-C − HDL-C)
Physical function [26]
Get up and go test: Participants began seated with their arms
folded across their chest. On the command go they rose from
the chair, without using their arms, and walked 6m, as fast
as possible without running, before sitting down on a chair.
This was repeated two times with the average time taken
Loaded 50m walk test: Participants were instructed
to walk 50m, as fast as possible without running, whilst
carrying 20% of their bodyweight for males and 15% of
their bodyweight for females. This was repeated two times
with the average time taken reported.
Step test: Participants were instructed to ascend the
nine stairs (each stair had a height of 16cm) as quickly as
they could. Power was calculated as the product of (total
vertical height of the stairs/time) × (body weight × 9.81).
SIT intervention
All SIT sessions were fully supervised and took place at
Abertay University. A bioharness 2 (Zephyr Technology,
Annapolis, USA) was attached to participants prior to the
training session to allow continuous recording of heart
rate (bpm) and breathing frequency. Participants then com-
pleted 6 × 6-s all-out effort cycle sprints, against 7% body-
weight for males and 6% bodyweight for females, with a
minimum of 60-s passive recovery or until heart rate was
below 120bpm. Passive recovery was chosen to allow the
heart rate to recover. The cycle sprint began once the par-
ticipant reached 100rpm. Each week one extra sprint was
added until the participants were completing ten sprints.
No warm-up or cool down was performed before or after
the session, with no adverse effects reported by any par-
ticipant. All participants completed 100% of the training
sessions. In week 1 training sessions averaged 8 ± 1.5min
and in week 10 training sessions averaged 11.6 ± 0.6min.
Table 1 Participant
characteristics, physical
function and circulating lipids
a p<0.05 SIT post versus control post
b p<0.01 SIT post versus control post
Pre Post Pre Post
Participant characteristics
Age (years) 66 ± 2 66 ± 2 66 ± 4 66 ± 4
Height (cm) 164 ± 10 164 ± 10 169 ± 9 169 ± 9
Weight (kg) 70 ± 13 71 ± 13 77 ± 13 75 ± 12a
BMI (kgm−2)25.9 ± 3.3 26.2 ± 3.5 26.9 ± 3.5 26.3 ± 3.5
Blood measures
Total cholesterol (mmoll−1)4.8 ± 1.4 4.8 ± 1.2 5.8 ± 1.5 4.6 ± 1.3
HDL cholesterol (mmoll−1)1.1 ± 0.4 1.2 ± 0.3 1.4 ± 0.4 1.5 ± 0.4
LDL cholesterol (mmoll−1)3.0 ± 0.9 2.9 ± 1.0 3.6 ± 1.1 2.6 ± 1.1
Total triglyceride (mmoll−1)1.2 ± 0.6 1.3 ± 0.8 1.7 ± 1.0 1.2 ± 0.7
TC:HDL-C 4.2 ± 0.7 4.0 ± 0.7 4.4 ± 1.1 3.2 ± 0.7b
LDL:HDL-C 2.7 ± 0.6 2.4 ± 0.7 2.7 ± 0.9 1.7 ± 0.6a
TG:HDL-C 1.4 ± 1.0 0.9 ± 0.6 1.0 ± 0.3 1.1 ± 0.6
Physical function
Get up and go (s) 6.9 ± 1.1 6.9 ± 1.0 7.4 ± 1.2 6.6 ± 1.0b
Loaded 50m walk (s) 37.3 ± 4.3 36.8 ± 4.0 38.3 ± 4.8 34.9 ± 5.1b
Stair climb power (W) 208 ± 86 200 ± 98 253 ± 46 285 ± 59a
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126 Sport Sciences for Health (2019) 15:123–131
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All tests were repeated at the same time of day, with the
same fast period and in the same order as baseline after
10weeks. There was 5 ± 2days between last training ses-
sion and retesting of participants. This was to ensure that a
training effect has being measured rather than a response to
the last training session.
Data andstatistical analysis
Heart rate area under the curve for the first 6 sprints in train-
ing session 1 and training session 20 was calculated using
the trapezoidal rule. Statistical analysis was carried out using
SPSS version 23. All data were checked for normal distribu-
tion using a Shapiro–Wilk test and was within normal values
for skewness and kurtosis. Independent samples t test was
used to determine the differences in baseline characteris-
tics between the groups. Effects of training on each variable
were analysed using an ANCOVA to determine difference
between groups. A one way repeated measures ANOVA was
used to analyse the heart rate area under the curve and aver-
age power data from training session 1 and training session
20. Significance was accepted as p < 0.05. Partial eta squared
(η2) was defined as 0.02 small, 0.13 medium and 0.26 large
as proposed by Bakeman [27]. A Pearson’s correlation was
carried out between dependent variables.
Blood pressure changes
There were no significant differences in blood pressure
variables between the control and SIT group at baseline or
between right and left arm blood pressure measures (Fig.1).
Following 10weeks of SIT, there was a significant reduc-
tion compared to control for both right and left arm sys-
tolic blood pressure (right arm: p < 0.01, η2 = 0.54; left arm:
p < 0.01, η2 = 0.61; Fig.1); right and left arm diastolic blood
pressure (right arm: p = 0.05, η2 = 0.24; lef t arm: p = 0.02,
η2 = 0.33; Fig.1); right and left arm pulse pressure (right
arm: p < 0.01, η2 = 0.55; left arm: p < 0.01, η2 = 0.53; Fig.1);
right and left arm mean arterial pressure (right arm: p = 0.01,
η2 = 0.37; left arm: p < 0.01, η2 = 0.49; Fig.1). Sex responses
are shown in Table2.
Fig. 1 Changes in vascular measures; a right arm systolic and diastolic blood pressure; b left arm systolic and diastolic blood pressure; c right
arm pulse pressure and mean arterial pressure; d left arm pulse pressure and mean arterial pressure. *p < 0.05 SIT post versus control post
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127Sport Sciences for Health (2019) 15:123–131
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Heart rate area underthecurve
There was no significant sprint × time interaction for aver-
age power (p = 0.358) between session 1 and session 20
(Fig.2). There was a significant sprint × time interaction
(p = 0.048, η2 = 0.17) for heart rate area under the curve
(Fig.2). Following 10weeks of SIT, heart rate AUC aver-
aged across the first six sprints of a SIT session was sig-
nificantly reduced (session 1: 6994 ± 372beatsmin−1s−1;
session 20: 6426 ± 153beatsmin−1s−1; p < 0.01). There
were no significant differences between the sessions for
sprints 1 and 2 (p > 0.05), however, there was a signifi-
cant difference between sessions for sprints 3, 4, 5 and 6
(p < 0.05, Fig.2).
Physical function
There were no significant differences in physical func-
tion between the control and SIT group at baseline
(Table1). Following 10weeks of SIT, there was a sig-
nificant improvement in physical function compared to
the control group (get up and go: p = 0.01, η2 = 0.44;
loaded 50m walk: p < 0.01, η2 = 0.50; stair climb power:
p = 0.04, η2 = 0.26; Table1). There is a significant corre-
lation between the change in pulse pressure and change in
get up and go (R = 0.55; p = 0.023) and loaded 50m walk
(R = 0.50; p = 0.041) but not with change in mean arterial
pressure (p > 0.05) or change in systolic blood pressure
(p > 0.05). Sex responses are shown in Table2.
Blood measures
There were no significant differences in blood measures
between the control and SIT group at baseline (Table1).
Following 10weeks of SIT, Total Cholesterol/HDL cho-
lesterol (p = 0.01, η2 = 0.42) and LDL cholesterol/HDL
cholesterol (p = 0.02, η2 = 0.34) were significantly reduced
compared to the control group (Table1). There was a trend
for reduction in total cholesterol (p = 0.07, η2 = 0.23), triglyc-
eride (p = 0.06, η2 = 0.24) and triglyceride/HDL cholesterol
(p = 0.06, η2 = 0.24; Table1).
The major finding from this study is that training twice
weekly, with each session lasting no longer than 12-min,
is sufficient to improve resting blood pressure and physi-
cal function in older adults. This demonstrates that reduc-
ing the training frequency does not impede adaptation to
sprint interval training in older adults. It could be pos-
sible that a further reduction in training frequency could
still promote health benefits in an older population. This
could have major implications as to how we encourage
older adults to exercise. It would appear that fewer train-
ing sessions are required than is currently recommended
for health benefits [20]. In the current study, there was
a significant reduction in left and right arm systolic and
diastolic blood pressure, pulse pressure and mean arterial
Table 2 Male and Female data
for blood pressure components
and physical function
R right arm, L left arm, BP blood pressure, Sys systolic, Dia diastolic, PP pulse pressure, MAP mean arte-
rial pressure, GUAG get up and go, L50m loaded 50m walk
SIT pre SIT post CONTROL pre CONTROL post
M (n = 6) F (n = 4) M (n = 6) F (n = 4) M (n = 3) F (n = 4) M (n = 3) F (n = 4)
BP (mmHg)
R Sys 136 ± 13 141 ± 13 122 ± 9 131 ± 6 137 ± 4 138 ± 13 149 ± 9 135 ± 6
R Dia 85 ± 5 85 ± 5 77 ± 9 84 ± 4 82 ± 9 76 ± 8 87 ± 5 74 ± 6
L Sys 138 ± 14 137 ± 15 122 ± 11 131 ± 7 137 ± 6 135 ± 15 146 ± 4 137 ± 7
R Sys 84 ± 5 82 ± 7 77 ± 7 78 ± 11 81 ± 9 75 ± 9 87 ± 7 74 ± 7
PP (mmHg)
Right 53 ± 8 56 ± 13 45 ± 6 54 ± 14 54 ± 4 60 ± 15 62 ± 3 62 ± 13
Left 57 ± 14 55 ± 14 48 ± 5 52 ± 10 55 ± 5 61 ± 15 59 ± 6 61 ± 11
MAP (mmHg)
Right 104 ± 9 94 ± 8 94 ± 10 88 ± 11 96 ± 4 86 ± 12 106 ± 5 96 ± 9
Left 104 ± 8 93 ± 7 94 ± 8 87 ± 12 94 ± 7 83 ± 11 104 ± 7 90 ± 8
GUAG (s) 8.0 ± 1.2 6.5 ± 0.6 7.0 ± 1.1 5.9 ± 0.4 6.4 ± 1.2 7.2 ± 1.2 6.7 ± 1.6 7.0 ± 0.6
L50m (s) 39 ± 5 36 ± 4 36 ± 6 33 ± 3 35 ± 4 39 ± 4 34 ± 4 39 ± 3
Power (W) 269 ± 54 229 ± 13 317 ± 56 236 ± 10 272 ± 99 159 ± 19 264 ± 99 152 ± 21
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128 Sport Sciences for Health (2019) 15:123–131
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pressure in older adults after 10 weeks of training. We
also demonstrate an improved heart rate recovery in older
adults when performing repeated sprint exercise. Further,
we also demonstrate that 10-week sprint interval train-
ing lowers circulating lipid profile in older adults. This
suggests that SIT could be a useful exercise paradigm to
reduce cardiovascular disease risk in older adults.
Blood pressure changes
Systolic blood pressure (7%), diastolic blood pressure (9%),
pulse pressure (9%) and mean arterial pressure (8%) were
all significantly reduced with a medium to large effect size
(η2 0.24 for all measures; Fig.1) following twice weekly
SIT. In normotensive young men and women longer duration
intervals performed on 3days per week have been shown to
reduce systolic and diastolic blood pressure by 2–7% and
mean arterial pressure by 6% [20, 28]. Given our findings
are of a similar magnitude, even though total weekly dura-
tion is much lower, then this suggests that the duration of the
sprint is not a driving factor in blood pressure adaptation to
SIT. Ejection fraction does not appear to change with either
endurance training [4] or with 30-s repeated high intensity
bursts [29] and resting heart rate was unchanged in this study
(data not reported). It could be speculated that improve-
ments in pulse pressure at rest, reported in this study, reflect
changes in arterial stiffness or wave reflection. The reduction
in MAP (8%) is similar to that seen in obese adults (6%)
after 2-week of 4–6 30-s sprints [30], but greater than that
reported in young people following 1–6 30-s sprints [31].
Obesity like ageing is associated with an increase in total
peripheral resistance that may reflect endothelial dysfunc-
tion [32]. Therefore, the reduction in mean arterial pressure
may reflect improved endothelial function seen in other SIT
protocols [31]. Given that hypertension is the most common
risk factor for cardiovascular morbidity and mortality across
the lifespan [33], then twice-weekly 6-s SIT is an effective
intervention to lower hypertension risk in older adults.
Heart rate area underthecurve
Following 10weeks of SIT, heart rate AUC during sprints
and recovery was significantly reduced by 8% (Fig.2). This
reduction in heart rate AUC occurs despite the average
power produced across the six sprints being similar (Fig.2).
This reduction in heart rate AUC following SIT could be
related to altered autonomic function. Short duration sprints
(8s sprint with 12s recovery over 20min) have been shown
to alter autonomic control of the heart via greater vagal
influence on heart rate at rest in young overweight women
[34]. When looking at the individual heart rate trace there
is a reduction in peak heart rate following each sprint, with
a more rapid recovery after exercise (Fig.2). This suggests
that there is either lower sympathetic activity post training
or withdrawal of vagal tone [35] during each sprint result-
ing in a lower heart rate response. Given that HR recovery
is associated with several pathophysiological abnormalities
and is considered as an independent risk factor for the devel-
opment of cardiovascular disease [33] these findings may
have important clinical implications for older adults.
Fig. 2 Changes in heart rate during training; a average power across
the first six sprints; b heart rate area under the curve for each sprint
and recovery period; c example trace of heart rate across 6 sprints.
*p < 0.05 session 1 compared to session 20
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129Sport Sciences for Health (2019) 15:123–131
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Lipid profile
The ratio of total cholesterol/HDL cholesterol (26%) and LDL
cholesterol/HDL cholesterol (33%) were significantly reduced
compared to control (Table2) following SIT, with a strong
trend for reduction of circulating total cholesterol (19%) and
triglyceride levels (23%; Table2). The magnitude of change
is similar to that reported in older adults following a 3 times
per week endurance programme lasting 50min per session
[36] and a treadmill-based sprint protocol in inactive females,
consisting of 10 × 15s sprints with 30s rest on 3days per week
[37]. However, SIT was only performed on 2days per week
compared to the 3days per week in endurance and run-based
high intensity with a much lower total sprint time. This may
reflect increased clearance of lipids from the blood or reduced
secretion of lipids from the liver. Fat oxidation has been shown
to be increased following longer duration SIT protocols [38]
and VLDL secretion has been shown to be reduced following
long duration (4min intervals) high intensity training [39].
However, this remains to be determined with this short sprint
Physical function
Following 10weeks of twice per week SIT, there was a sig-
nificant improvement in get up and go (11%), loaded 50m
walk (9%) and stair climb power (dpcc2 ≥ − 0.8 for all meas-
ures Table2). In older adults, a 10-week endurance training
programme, carried out 3days per week for 50min, resulted
in a 15% reduction in 1 mile walk [36]. Likewise, a 14-week
progressive resistance training programme improved timed get
up and go by 15% [40]. The improvements in physical func-
tion are similar to those reported after 6 weeks of 6s SIT, 7%
improvement in loaded 50m walk, 7% improvement in get up
and go [22], suggesting that improvements in physical func-
tion occur early during SIT but continue to improve as train-
ing progresses. There is a significant correlation between the
change in resting pulse pressure and the change in loaded 50m
walk (R = 0.5; p = 0.04) and get up and go (R = 0.55; p = 0.02).
This is similar to the correlation reported for improvements in
arterial stiffness and physical function with endurance exercise
[6]. Given at rest in the elderly, pulse pressure reflects either
arterial stiffness or wave amplification then this suggests that
changes within the blood vessel structure are important for
physical function adaptations following SIT. Further these
adaptations are seen within only twice weekly training ses-
sions lasting approximately 10min.
In this study, we show for the first time the adaptation
in blood pressure and physical function in older adults
to a twice-weekly extremely short duration SIT. These
results should be considered in context of the limitations
of the study and future studies should look to record all
medication being taken by participants and seek to record
daily activity and nutritional intake across the intervention
period. However, there are significant improvements in
vascular and physical function and these improvements in
physical function are strongly correlated to the improve-
ments in pulse pressure (R = 0.55), which may reflect
greater arterial compliance following SIT. Given that one
of time and dislike of traditional exercise are barriers to
participation [20] then there is a need to reappraise current
exercise advice for older adults to do 150min of moderate
or 75min of vigorous intensity exercise a week [41]. The
current study has a much lower time commitment but more
research is required to determine minimum effective train-
ing load of SIT to promote optimal aging in older adults.
Acknowledgements This project was supported by Abertay University.
Compliance with ethical standards
Conflict of interest The authors declare no conflict of interest.
Ethical approval The study was granted ethical approval by the insti-
tutional ethics committee (SHS0701615) and was carried out in line
with the Declaration of Helsinki (World Medical Association 2013).
Informed consent All participants were given verbal and written infor-
mation about the study prior to providing informed consent.
Open Access This article is distributed under the terms of the Crea-
tive Commons Attribution 4.0 International License (http://creat iveco
mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribu-
tion, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
1. Scuteri A, Najjar SS, Muller DC, Andres R, Hougaku H, Mette
EJ etal (2004) Metabolic syndrome amplifies the age-associated
increases in vascular thickness and stiffness. J Am Coll Cardiol
2. Asmar R, Rudnichi C, Blacher J, London GM, Safar ME (2001)
Pulse pressureand aortic wave are markers of cardiovascular
risk in hypertensive populations. AJH 14:91–97
3. Port S, Cobb FR, Coleman RE, Jones RH (1980) Effect of age
on the response of the left ventricular ejection fraction to exer-
cise. N Engl J Med 303:1133–1137
4. Stratton JR, Levy WC, Schwartz RS, Abrass IB, Cerque-
ira MD (1994) Beta-adrenergic effects on left ventricular
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
130 Sport Sciences for Health (2019) 15:123–131
1 3
filling: influence of aging and exercise training. J Appl Physiol
5. Vaccarino V, Berger A, Abramson J, Black H, Setaro J, Davey J
etal (2001) Pulse pressure and risk of cardiovascular events in
the systolic hypertension in the elderly program. Am J Cardiol
6. Brunner EJ, Shipley MJ, Witte DR, Singh-Manoux A, Britton
AR, Tabak AG etal (2011) Arterial stiffness, physical function,
and functional limitation: the Whitehall II study. Hypertension
7. Ferrier KE, Muhlmann MH, Baguet JP, Cameron JD, Jennings
GL, Dart AM etal (2002) Intensive cholesterol reduction low-
ers blood pressure and large artery stiffness in isolated systolic
hypertension. J Am Coll Cardiol 39:1020–1025
8. DeFronzo RA (1981) Glucose intolerance and aging. Diabetes
Care 4:493–501
9. Chubert CM, Rogers NL, Remsberg KE, Sun SS, Chumlea WC,
Demerath EW etal (2006) Lipids, lipoproteins, lifestyle, adiposity
and fat-free mass during middle age: the Fels longitudinal study.
Int J Obes 30:251–260
10. Nomikos T, Panagiotakos D, Georgousopoulou E, Metaxa V,
Chrysohoou C, Skoumas I etal (2015) Hierarchical modelling of
blood lipids’ profile and 10-year (2002–2012) all cause mortal-
ity and incidence of cardiovascular disease: the ATTICA study.
Lipids Health Dis 14:108
11. Blacher J, Asmar R, Djane S, London GM, Safar ME (1999)
Aortic pulse wave velocity as a marker of cardiovascular risk in
hypertensive patients. Hypertension 33:1111–1117
12. Wilkinson I, Cockcroft JR (2007) Cholesterol, Lipids and arte-
rial stiffness. Safar ME, Frohlich ED (eds) Atherosclerosis, large
arteries and cardiovascular risk. Advances in cardiology, vol 44.
Karger, Basel, pp261–277
13. Yang SJ, Hong HC, Choi HY, Yoo HJ, Hwang TG, Baik SH, Choi
DS, Kim SM, Choi KM (2011) Effects of a three-month combined
exercise programme on fibroblast growth factor 21 and fetuin-
A levels and arterial stiffness in obese women. Clin Endocrinol
14. Taniguchi H, Tanisawa K, Sun X, Kubo K, Higuchi M (2016)
Endurance exercise reduces hepatic fat content and serum fibro-
blast growth factor 21 levels in elderly men. J Clin Endocrinol
Metab 101:191–198
15. McPhee JS, French DP, Jackson D, Nazroo J, Pendleton N, Degens
H (2016) Physical activity in older age: perspectives for healthy
ageing and frailty. Biogerontology 17:567–580
16. Adamson S, Lorimer R, Cobley JN, Lloyd R, Babraj J (2014) High
intensity training improves health and physical function in middle
aged adults. Biology (Basel) 3:333–344
17. Burgomaster KA, Cermak NM, Phillips SM, Benton CR, Bonen
A, Gibala MJ (2007) Divergent response of metabolite transport
proteins in human skeletal muscle after sprint interval train-
ing and detraining. Am J Physiol Regul Integr Comp Physiol
18. Burgomaster KA, Hughes SC, Heigenhauser GJ, Bradwell SN,
Gibala MJ (2005) Six sessions of sprint interval training increases
muscle oxidative potential and cycle endurance capacity in
humans. J Appl Physiol 98:1985–1990
19. Metcalfe RS, Babraj JA, Fawkner SG etal (2012) Towards the
minimal amount of exercise for improving metabolic health: ben-
eficial effects of reduced-exertion high-intensity interval training.
Eur J Appl Physiol 112:2767–2775
20. Gillen JB, Percival ME, Skelly LE etal (2014) Three minutes of
all-out intermittent exercise per week increases skeletal muscle
oxidative capacity and improves cardiometabolic health. PLoS
One 9(11):e111489
21. Yamagishi T, Babraj J (2017) Effects of reduced-volume of sprint
interval training and the time course of physiological and perfor-
mance adaptations. Scand J Med Sci Sports 7:1662–1672
22. Adamson SB, Lorimer R, Cobley JN, Babraj J (2014) Extremely
short-duration high-intensity training substantially improves the
physical function and self-reported health status of elderly adults.
J Am Geriatr Soc 62:1380–1381
23. Dumville JC, Hahn S, Miles JN, Torgerson DJ (2006) The use of
unequal randomisation ratios in clinical trials: a review. Contemp
Clin Trials 27:1–12
24. Clark CE, Taylor RS, Shore AC, Ukoumunne OC, Campbell
JL (2012) Association of a difference in systolic blood pressure
between arms with vascular disease and mortality: a systematic
review and meta-analysis. Lancet 379:905–914
25. Chen Y, Zhang X, Pan B, Jin X, Yao H, Chen B etal (2010) A
modified formula for calculating low-density lipoprotein choles-
terol values. Lipids Health Dis 9:52
26. Bennell K, Dobson F, Hinman R (2011) Measures of physical
performance assessments. Arthritis Care Res 63:S350–S370
27. Bakeman R (2005) Recommended effect size statistics for
repeated measures designs. Behav Res Methods 37:379–384
28. Ciolac EG, Bocchi EA, Bortolotto LA, Carvalho VO, Greve JM,
Guimarães GV (2010) Effects of high-intensity aerobic interval
training vs. moderate exercise on hemodynamic, metabolic and
neuro-humoral abnormalities of young normotensive women at
high familial risk for hypertension. Hypertens Res 33:836–843
29. Eskelinen JJ, Heinonen I, Löyttyniemi E, Hakala J, Heiskanen
MA, Motiani KK, Virtanen K, Pärkkä JP, Knuuti J, Hannukainen
JC, Kalliokoski KK (2016) Left ventricular vascular and meta-
bolic adaptations to high-intensity interval and moderate intensity
continuous training: a randomized trial in healthy middle-aged
men. J Physiol 59:7127–7140
30. Whyte LJ, Gill JM, Cathcart AJ (2010) Effect of 2 weeks of sprint
interval training on health-related outcomes in sedentary over-
weight/obese men. Metabolism 59:1421–1428
31. Rakobowchuk M, Tanguay S, Burgomaster KA, Howarth KR,
Gibala MJ, MacDonald MJ (2008) Sprint interval and traditional
endurance training induce similar improvements in peripheral
arterial stiffness and flow-mediated dilation in healthy humans.
Am J Physiol Regul Integr Comp Physiol 295:236–242
32. Wildman RP, Mackey RH, Bostom A, Thompson T, Sutton-Tyrrell
K (2003) Measures of obesity are associated with vascular stiff-
ness in young and older adults. Hypertension 42:468–473
33. Ciolac EG (2012) High-intensity interval training and hyperten-
sion: maximizing the benefits of exercise? Am J Cardiovasc Dis
34. Boutcher SH, Park Y, Dunn SL, Boutcher YN (2013) The relation-
ship between cardiac autonomic function and maximal oxygen
uptake response to high-intensity intermittent-exercise training. J
Sports Sci 31:1024–1029
35. White DW, Raven PB (2014) Autonomic neural control of heart
rate during dynamic exercise: revisited. J Physiol 592:2491–2500
36. Fahlman MM, Boardley D, Lambert CP, Flynn MG (2002) Effects
of endurance training and resistance training on plasma lipopro-
tein profiles in elderly women. J Gerontol A Biol Sci Med Sci
37. Zaer Ghodsi N, Zolfaghari MR, Fattah A (2016) The impact of
high intensity interval training on lipid profile, inflammatory
markers and anthropometric parameters in inactive women. Med
Lab J 10:56–60
38. Boutcher SH (2011) High-intensity intermittent exercise and fat
loss. J Obes 2011:868305
39. Tsekouras YE, Magkos F, Kellas Y, Basioukas KN, Kavouras
SA, Sidossis LS (2008) High-intensity interval aerobic training
reduces hepatic very low-density lipoprotein-triglyceride secretion
rate in men. Am J Physiol Endocrinol Metab 295:851–858
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
131Sport Sciences for Health (2019) 15:123–131
1 3
40. Sousa N, Sampaio J (2005) Effects of progressive strength training
on the performance of the Functional Reach Test and the Timed
Get-Up-and-Go Test in an elderly population from the rural north
of Portugal. Am J Hum Biol 17:746–751
41. Elsawy B, Higgins KE (2010) Physical activity guidelines for
older adults. Am Fam Physician 81:55–59
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... Because of this need, the objective of this study is to verify the chronic effects of IT with different intensities on hemodynamic, autonomic and cardiorespiratory variables of physically active older people. Our hypothesis was that somehow, protocols with different intensities of IT could offer (positive) changes in the dependent variables researched here, with these being hemodynamic [37], autonomic [18] and cardiorespiratory [24]. ...
... A sample calculation was performed (G*power) [53], anticipating a "large" effect size (f = 0.4), with an α = 0.05, a statistical power of (1 − β) = 0.95, the correlated dependent variables with an r = 0.50, and a violation of sphericity (ε) = 0.80, will require a total sample size of 21 individuals and an enabled power of 0.95. The suggested effect size and the remaining parameters were defined according to similar studies that evaluated changes in cardioprotective variables during exercise protocols of the elderly [18,24,37]. ...
... In addition to Pichot et al. [18], other experiments also obtained positive responses in HRV (p < 0.05) after the intervention with IT [25,28]. For a cardiorespiratory assessment, the IT was shown to have potential in the results, significantly improving (p < 0.05) VO 2max [18,[35][36][37]. These findings are essential since the elderly reduce approximately 5% and 10% of cardiorespiratory capacity for active and sedentary individuals, respectively [47]. ...
Full-text available
Interval training (IT) is a very efficient method. We aimed to verify the chronic effects of IT with different intensities on hemodynamic, autonomic and cardiorespiratory variables in the elderly. Twenty-four physically active elderly men participated in the study and were randomized into three groups: Training Group A (TG A , n = 8), Training Group B (TG B , n = 8) and control group (CG, n = 8). The TG A and TG B groups performed 32 sessions (48 h interval). TG A presented 4 min (55 to 60% of HRmax) and 1 min (70 to 75% of HRmax). The TGB training groups performed the same protocol, but performed 4 min at 45 to 50% HRmax and 1 min at 60 to 65% HRmax. Both training groups performed each set six times, totaling 30 min per session. Assessments were performed pre (baseline) after the 16th and 32nd intervention session. The CG performed only assessments. Hemodynamic, autonomic and cardiorespiratory (estimated VO 2max) variables were evaluated. There were no significant differences between protocols and times (p > 0.05). However, the effect size and percentage delta indicated positive clinical outcomes, indicating favorable responses of IT. IT may be a strategy to improve hemodynamic, autonomic and cardiorespiratory behavior in healthy elderly people.
... 5-6 s; e.g. (Adamson et al., 2019(Adamson et al., , 2020], on the basis that they may be perceived to be more palatable for previously inactive or unfit individuals . There is accumulating evidence that such protocols remain efficacious for improving key biomarkers of cardiovascular and metabolic health in target populations (Metcalfe et al., 2012;Gillen et al., 2016;Adamson et al., 2019Adamson et al., , 2020, but an apparent lack of evidence regarding their impact on affective responses. ...
... (Adamson et al., 2019(Adamson et al., , 2020], on the basis that they may be perceived to be more palatable for previously inactive or unfit individuals . There is accumulating evidence that such protocols remain efficacious for improving key biomarkers of cardiovascular and metabolic health in target populations (Metcalfe et al., 2012;Gillen et al., 2016;Adamson et al., 2019Adamson et al., , 2020, but an apparent lack of evidence regarding their impact on affective responses. Accordingly, there is considerable merit in establishing how various SIE protocol permutations may impact affective responses during acute SIE and, by extension, which (if any) protocols are most likely to be associated with high levels of adherence. ...
... Thus, although SIE will lead to reduced valence, our analysis shows that negative valence could be avoided with SIE protocols with a total time commitment of up to ∼10 min per session (Niven et al., 2018;Bradley et al., 2019;Songsorn et al., 2019;Astorino et al., 2020). This is important, as there is an accumulating body of evidence demonstrating that these SIE protocols are still associated with meaningful improvements in cardiorespiratory fitness as well as other markers of cardiometabolic health (Metcalfe et al., 2012;Adamson et al., 2019Adamson et al., , 2020. Overall, this metaanalysis provides further evidence that SIE protocols should employ a minimal number of sprint repetitions, as this (1) improves time-efficiency, (2) attenuates the decrease in affective valence, and (3) does not appear to impact health related adaptations to training. ...
Full-text available
Responses to sprint interval exercise (SIE) are hypothesized to be perceived as unpleasant, but SIE protocols are diverse, and moderating effects of various SIE protocol parameters on affective responses are unknown. We performed a systematic search to identify studies (up to 01/05/2021) measuring affective valence using the Feeling Scale during acute SIE in healthy adults. Thirteen studies involving 18 unique trials and 316 unique participant (142 women and 174 men) affective responses to SIE were eligible for inclusion. We received individual participant data for all participants from all studies. All available end-of-sprint affect scores from each trial were combined in a linear mixed model with sprint duration, mode, intensity, recovery duration, familiarization and baseline affect included as covariates. Affective valence decreased significantly and proportionally with each additional sprint repetition, but this effect was modified by sprint duration: affect decreased more during 30 s (0.84 units/sprint; 95% CI: 0.74–0.93) and 15–20 s sprints (1.02 units/sprint; 95% CI: 0.93–1.10) compared with 5–6 s sprints (0.20 units/sprint; 95% CI: 0.18–0.22) (both p < 0.0001). Although the difference between 15–20 s and 30 s sprints was also significant ( p = 0.02), the effect size was trivial ( d = −0.12). We observed significant but trivial effects of mode, sprint intensity and pre-trial familiarization, whilst there was no significant effect of recovery duration. We conclude that affective valence declines during SIE, but the magnitude of the decrease for an overall SIE session strongly depends on the number and duration of sprints. This information can be applied by researchers to design SIE protocols that are less likely to be perceived as unpleasant in studies of real-world effectiveness. Systematic Review Registration Open Science Framework, .
... While all studies were of participants without contraindications to exercise training, five studies [42, 47,52,54,60] reported mixed health conditions and two studies [51,55] did not disclose participant health status. Three studies [50,58,59] were specifically of chronic obstructive pulmonary disease (COPD) patients, two studies [56,61] were of coronary artery disease patients, and there was one study each of patients with mild-to-moderate Alzheimer's disease [40], chronic heart failure [56], controlled hypertension [62], and obesity [52]. Two studies [48,49] described participants as healthy. ...
... Green circle = low risk of bias Yellow triangle = unclear risk of bias Red diamond = high risk of bias Adamson et al. [43] Ballesta-Garcia et al. [52] Bellumori et al. [46] Bouaziz et al. [60] Boukabous et al. [58] Coetsee and Terblanche [53] Enette et al. [45] Gloeckl et al. [64] Ikenaga et al. [56] Jaureguizar et al. [62] Koufaki et al. [63] Mador et al. [55] Nasis et al. [65] Reichert et al. [66] Siqueira-Andrade et al. [57] Tavoian et al. [54] Wolszakiewicz et al. [59] ...
Full-text available
Background Preserving physiological functional capacity (PFC), the ability to perform the activities of daily life, and the ease with which they can be performed, in older adults, defined for this study as ≥ 50 years of age, is an important consideration for maintaining health and independence through the ageing process. Physical activity, and exercise training in particular, has been positively associated with improvement in PFC. In addition to improving aerobic and anaerobic capacity, promoting and preserving functional movement as a component of PFC is an important goal of physical activity, especially for older adults. High-intensity interval training (HIIT), an exercise protocol where repeated bouts of increased intensity are interspersed with active or passive recovery periods, has often been studied as an alternative to traditional moderate-intensity continuous training (MICT) exercise, where a continuous intensity is maintained throughout the exercise session. A large body of research has determined that both types of exercise programme are effective in improving measures of aerobic and anaerobic fitness in older adults. However, the effect of the two exercise modalities on functional movement has most often been a secondary outcome, with a range of observational techniques applied for measurement. Objectives The primary objective of this research is to systematically review and meta-analyse published studies of HIIT interventions that measured functional movement in older adults to conclude if HIIT is effective for improving functional movement. A secondary objective is to determine if there are significant differences between HIIT and MICT effect on functional movement. Methods A search strategy of terms locating studies of HIIT interventions, functional movement outcome measures, and older adult population samples was executed on seven digital databases. Randomized and pair-matched trials of > 2 weeks were considered for inclusion. Studies of participants with neurological impairment or studies using combined exercise modality were rejected. Standardized mean difference for functional movement outcome measures was calculated. A meta-analysis of the included studies and subgroups was performed along with study quality (risk of bias and publication bias) evaluation. Results A total of 18 studies were included in random effects model pooled analysis. Subgroup analysis of HIIT versus MICT on functional movement showed a trivial effect in favour of HIIT (ES 0.13, 95% CI [−0.06, 0.33] p = 0.18) and did not achieve statistical significance. However, HIIT showed a medium, statistically significant favourable effect on functional movement versus non-intervention control (ES = 0.60 95% CI [0.24, 0.95] p = 0.001). Further subgroups analysis using singular and multiple functional movement outcome measures showed similar results. Conclusion This meta-analysis indicates that HIIT interventions in older adults may be effective at promoting improvements in functional movement, though it is unclear whether HIIT is superior to MICT.
... Existing studies on supramaximal HIT for older adults have shown promising results (21)(22)(23). However, they suffer from small sample sizes, the use of inactive control groups or lack of control conditions entirely, strict experimental settings, and one-to-one supervision. ...
Full-text available
Background: This study examined the effects of regulated and controlled supramaximal high-intensity interval training (HIT) adapted for older adults, compared to moderate-intensity training (MIT), on cardiorespiratory fitness; cognitive, cardiovascular, and muscular function; and quality of life. Methods: Sixty-eight nonexercising older adults (66-79 years, 44% males) were randomized to 3 months of twice-weekly HIT (20-minute session including 10 × 6-second intervals) or MIT (40-minute session including 3 × 8-minute intervals) on stationary bicycles in an ordinary gym setting. Individualized target intensity was watt controlled with a standardized pedaling cadence and individual adjustment of the resistance load. Primary outcomes were cardiorespiratory fitness (V̇o2peak) and global cognitive function (unit-weighted composite). Results: V̇o2peak increased significantly (mean 1.38 mL/kg/min, 95% CI [0.77, 1.98]), with no between-group difference (mean difference 0.05 [-1.17, 1.25]). Global cognition did not improve (0.02 [-0.05, 0.09]), nor differed between groups (0.11 [-0.03, 0.24]). Significant between-group differences in change were observed for working memory (0.32 [0.01, 0.64]), and maximal isometric knee extensor muscle strength (0.07 N·m/kg [0.003, 0.137]), both in favor of HIT. Irrespective of the group, there was a negative change in episodic memory (-0.15 [-0.28, -0.02]), a positive change in visuospatial ability (0.26 [0.08, 0.44]), and a decrease in systolic (-2.09 mmHg [-3.54, -0.64]) and diastolic (-1.27 mmHg [-2.31, -0.25]) blood pressure. Conclusions: In nonexercising older adults, 3 months of watt-controlled supramaximal HIT improved cardiorespiratory fitness and cardiovascular function to a similar extent as MIT, despite half the training time. In favor of HIT, there was an improvement in muscular function and a potential domain-specific effect on working memory. Clinical trial registration: NCT03765385.
... With regard to hemodynamic responses (i.e., HR and BP), better neuro-cardiac adaptations and the renin-angiotensin system may be responsible for positive changes in this system. Additionally, reductions in arterial stiffness, endothelial function, and plasma volume can also occur in response to improved cardiovascular performance [35]. For the VO 2max , the improved transport and delivery of O 2 to tissues due to higher hemoglobin and myoglobin are part of the long-term improvement in the VO 2max [36]. ...
Full-text available
This paper investigated the effects over time of different forms of neuromuscular training on hemodynamic responses, the estimated VO2max, and walking performance. 105 older adults were randomly organized into three groups: RGA, RGB, and the Control Group (CG). RGA and RGB did 4 weeks of adaptation phase training and 12 weeks of intervention with different loads: moderate loads for RGB. and higher loads for RGA. A pre- and post-evaluation of the resting heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), double product (DP), estimated VO2max, and walking performance were assessed. Significant differences were observed for SBP, DBP, HR, and DP. For SBP, a post-evaluation reduction was observed only in RGA (p = 0.007) and when comparing RGA with the Control Group (p < 0.000). For the absolute VO2max, a significant improvement was seen in RGB compared to RGA (p = 0.037) and CG (p < 0.000). For the relative VO2max, RGB scored significantly higher than RGA (p < 0.000) and CG (p < 0.000), post-intervention. For the walk test, a significant reduction in completion times was observed for RGA (p = 0.027) and RGB (p < 0.000), and for RGB compared to RGA (p = 0.000) and CG (p < 0.000). Resistance training can be an excellent strategy for hemodynamic and cardiorespiratory improvement in the elderly.
... To the best of our knowledge, the present study is the first to employ the conventional SIT exercise paradigm (Gibala and McGee, 2008) in older adults. Previous studies evaluating the cardiovascular effects of vigorous exercise involved either the classic high intensity interval training approach (e.g., three-to-five ~4 min bouts of severe-intensity exercise (Keating et al., 2020)) or alternative, and likely less strenuous, versions of the traditional SIT protocol (e.g., three or six sprints of 20 or 6 s, respectively (Adamson et al., 2019;Yasar et al., 2019); three 20-s static running sprints (Yasar et al., 2021)). The paucity of data regarding the use of SIT in older adults likely reflects the safety concerns related to performing repeated all-out efforts in this population. ...
An acute session of sprint interval training (SIT) is a potent stimulus for the metabolic and cardiovascular systems. However, the feasibility of SIT in older adults and its effectiveness to acutely improve aerobic function by transiently accelerating the rate of adjustment of oxidative phosphorylation quantified by V̇O2 kinetics (τV̇O2) are unknown. This study evaluated the time course of changes of τV̇O2 in response to different doses of SIT in older inactive adults compared to their young counterparts. Eight older (age: 67 ± 3 years) and eight young (age: 30 ± 3 years) adults completed three separate SIT sessions consisting of either one (SIT1), three (SIT3), or five (SIT5) consecutive bouts of SIT. Each SIT intervention was interspersed by a two-week recovery phase. The bike resistance during the sprints was set at 0.065 kg·kg⁻¹ body mass for older and 0.075 kg·kg⁻¹ body mass for young adults. Moderate-intensity step-transitions were performed to assess τV̇O2 before (PRE) and one (1d), two (2d) and three (3d) days post each SIT intervention. Older adults attained lower peak power outputs, average power output, and blood lactate concentrations across all sprints of each SIT intervention compared to young (P < 0.01). Following SIT1, τV̇O2 was faster at 1d (−13.6%; P = 0.008) and 2d (−12.7%; P = 0.017) and returned to values similar to PRE at 3d (+0.4%; P > 0.05) in both older and young. Following SIT3, τV̇O2 was faster at 1d (−20.6%; P < 0.001), 2d (−18.5%; P = 0.011), and 3d (−14.5%; P = 0.045) compared to PRE in both older and young. Following SIT5, τV̇O2 became faster in older (at 1d, 2d, and 3d; ~25%; P < 0.05) but remained unchanged in young with respect to PRE (P > 0.05). These findings indicate that SIT has the potency to acutely improve aerobic function by speeding the rate of adjustment of oxidative phosphorylation. However, only older adults were able to maintain these beneficial effects when the volume of SIT was maximized (SIT5). Future studies are warranted to evaluate the long-term feasibility of SIT in older adults.
... Practically, the recent recommendations for immunoprotective exercise are as follows: intensity of exercise should be 60-75% of HRmax or 50-60% of V O2max with rating of perceived exertion (RPE) of 10-14/20, frequency of exercise being 3-5 days/week and sessions ranging from 20 to 60 min [108]. Moreover, 75 minutes per week of specific high-intensity interval training (HIIT, with single session up to 10 min) is considered to be an effective strategy to achieve optimal functionality of the immune system in the elderly [120]. In the framework of HIIT also resistance training (e.g., bodyweight exercises) with sets of short exercise (< 1 min) or low number of repetitions (< 12 reps per set) and higher speeds of movement would be beneficial in older individuals [121]. ...
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Aging is a complex, multietiological process and a major risk factor for most non-genetic, chronic diseases including geriatric syndromes that negatively affect healthspan and longevity. In the scenario of "healthy or good aging", especially during the COVID-19 era, the proper implementation of exercise as "adjuvant" or "polypill" to improve disease-related symptoms and comorbidities in the general population is a top priority. However, there is still a gap concerning studies analyzing influence of exercise training to immune system in older people. Therefore, the aim of this review is to provide a brief summary of well-established findings in exercise immunology and immunogerontology, but with a focus on the main exercise-induced mechanisms associated with aging of the immune system (immunosenescence). The scientific data strongly supports the notion that regular exercise as a low-cost and non-pharmacological treatment approach, when adjusted on an individual basis in elderly, induce multiple rejuvenating mechanisms: (1) affects the telomere-length dynamics (a "telo-protective" effect), (2) promote short- and long-term anti-inflammatory effects (via e.g., triggering the anti-inflammatory phenotype), 3) stimulates the adaptive immune system (e.g., helps to offset diminished adaptive responses) and in parallel inhibits the accelerated immunosenescence process, (4) increases post-vaccination immune responses, and (5) possibly extends both healthspan and lifespan.
In this pandemic situation, there are many problems facing people from all over the world. For example, economic downgrades, family problems, illness, and health problems, etc. Indonesia is one of many countries facing this situation. With a record of being the fourth most populous country in the world, Indonesia easily creates a lot of problems in this pandemic situation. This pandemic situation has made the world aware of such problems in their lives. One of the important types of problems that arise from this awareness is the maintenance of physical health. Maintenance of physical health is very important for this pandemic situation. COVID-19 can really cause many diseases, and therefore, health maintenance is very important to get rid of this virus. Many media inform the public to take care of their physical health, but there are also many things that need to be considered and continue life as it is. Therefore, information explaining the importance of maintaining physical health is needed by people in Indonesia, and this study tries to review the importance of health maintenance. This data can be shown in of an app, where it is all currently done digitally, in conjunction also with COVID-19 pandemic that has resulted all people to become digitally literate. In addition, there is also the risk of access to meet other people if you have to consult a doctor, so making a physical health maintenance application during the COVID-19 pandemic will be very helpful. Various educations can be given to the public, such as educating the public that taking supplements/vitamins is important in preventing the COVID-19 virus. Consuming minerals and vitamins for endurance is indeed important during the current pandemic, because the body needs these substances to increase endurance. Apart from supplements, vitamin and mineral needs can also be obtained from various types of food. According to dietitian Maxine Smith, eating healthy foods is the best way to keep the immune system in balance, because the immune system relies heavily on nutritious food. This is because healthy foods contain various substances, including vitamins and minerals as immune support.KeywordsPhysical healthApplicationsCOVID-19 pandemicImmune
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Negative aspects of aging include a decrease in muscle mass/strength and maximal oxygen consumption (VO2max). The most beneficial and adaptable protocol among the various exercise methods should be explored in older adults. A combination of aerobic and strength training has been recommended as an effective and required exercise program to improve both VO2max and muscle mass/strength in guidelines. Recently, high-intensity interval training (HIIT) has become a popular and time-efficient way to perform vigorous exercise effectively, potentially improving VO2max and muscle strength/power as it is rendered as a combination of aerobic and strength exercise training. It is often used by young and middle-aged people with/without chronic disease. However, the adaptation of HIIT in older adults has not been fully established yet. The effects of submaximal HIIT on metabolic, physiological, muscle adaptation, and cognitive abilities have been observed in older adults. In contrast, there is only limited evidence on sprint interval training (supramaximal), which also affects muscle strength/power and VO2max in older adults. Because some barriers remain to be overcome when implementing HIIT in older adults, the applicable protocols should be explored with stratification by age and physical function. Furthermore, data on safety, clean-up methods, adherence to participation rate, and settled intensity during unsupervised training are still lacking and should be focused on in future studies.
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High-intensity interval training (HIIT) has been reported to become an alternative of moderate-intensity continuous training and adapted even in older adults. However, to implement the use of HIIT for older adults, who are very often associated with life-style related and chronic diseases, safety issues should be considered in the first place. However, at present, the evaluation of the safety of HIIT among older adults is compromised by the limited availability of relevant data due to the low proportion of studies reporting adverse events. In this review, update data regarding safety and check-up methods for older adults are described in submaximal HIIT and spring interval training.
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This study sought to determine the time course of training adaptations to two different sprint interval training programmes with the same sprint: rest ratio (1:8) but different sprint duration. Nine participants (M: 7; F: 2) were assigned to 15-second training group (15TG) consisting of 4-6 × 15-second sprints interspersed with 2-minute recovery, whereas eight participants (M: 5; F: 3) were assigned to 30-second training group (30TG) consisting of 4-6 × 30 second sprints interspersed with 4-minute recovery. Both groups performed their respective training twice per week over 9 weeks and changes in peak oxygen uptake (V˙O2peak) and time to exhaustion (TTE) were assessed every 3 weeks. Additional eight healthy active adults (M: 6; F: 2) completed the performance assessments 9 weeks apart without performing training (control group, CON). Following 9 weeks of training, both groups improved V˙O2peak (15TG: 12.1%; 30TG: 12.8%, P<.05) and TTE (15TG: 16.2%; 30TG: 12.8%, P<.01) to a similar extent. However, while both groups showed the greatest gains in V˙O2peak at 3 weeks (15TG: 16.6%; 30TG: 17.0%, P<.001), those in TTE were greatest at 9 weeks. CON did not change any of performance variables following 9 weeks. This study demonstrated that while the changes in cardiorespiratory function plateau within several weeks with sprint interval training, endurance capacity (TTE) is more sensitive to such training over a longer time frame in moderately-trained individuals. Furthermore, a 50% reduction in sprint duration does not diminish overall training adaptations over 9 weeks.
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Background and Objective: High-intensity interval training (HIIT) is a recently proposed exercise protocol, which is time-effective. The aim of this study was to evaluate the effect of HIIT for 8 weeks on the lipid profile, C-reactive protein (CRP), fasting blood sugar (FBS) and anthropometric parameters of young women who do not exercise. Methods: In this study, 20 young physically inactive women performed HIIT workouts for 8 weeks and 3 sessions per week. The training protocol consisted of 10-times treadmill running for 15 seconds at maximum effort and then 30 seconds of resting. Blood samples were taken while fasting, a day before and after the training and then the considered parameters were measured. Wilcoxon test was used to compare the obtained data. Results: HIIT significantly reduced FBS, cholesterol, low-density lipoprotein, high-density lipoprotein /cholesterol ratio and CRP while increasing the HDL levels. There was a significant difference in the weight, body fat percentage, waist circumference, abdominal circumference and chest circumference of the subjects before and after the training (p
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Key points: High-intensity interval training (HIIT) has become popular, time-sparing alternative to moderate intensity continuous training (MICT), although the cardiac vascular and metabolic effects of HIIT are incompletely known. We compared the effects of 2-week interventions with HIIT and MICT on myocardial perfusion and free fatty acid and glucose uptake. Insulin-stimulated myocardial glucose uptake was decreased by training without any significantly different response between the groups, whereas free fatty acid uptake remained unchanged. Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P = 0.03 for interaction) and was correlated with myocardial glucose uptake for the entire dataset and especially after HIIT training. HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT, and this should be considered when prescribing very intense HIIT for previously untrained subjects. Abstract: High-intensity interval training (HIIT) is a time-efficient way of obtaining the health benefits of exercise, although the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n = 14 in both) and underwent six cycle ergometer training sessions within 2 weeks (HIIT session: 4-6 × 30 s all-out cycling/4 min recovery, MICT session 40-60 min at 60% V̇O2 peak ). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography was used to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, although no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU was decreased by training (HIIT from 46.5 to 35.9; MICT from 47.4 to 44.4 mmol 100 g(-1) min(-1) , P = 0.007 for time, P = 0.11 for group × time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P = 0.03 for group × time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects.
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Regular physical activity helps to improve physical and mental functions as well as reverse some effects of chronic disease to keep older people mobile and independent. Despite the highly publicised benefits of physical activity, the overwhelming majority of older people in the United Kingdom do not meet the minimum physical activity levels needed to maintain health. The sedentary lifestyles that predominate in older age results in premature onset of ill health, disease and frailty. Local authorities have a responsibility to promote physical activity amongst older people, but knowing how to stimulate regular activity at the population-level is challenging. The physiological rationale for physical activity, risks of adverse events, societal and psychological factors are discussed with a view to inform public health initiatives for the relatively healthy older person as well as those with physical frailty. The evidence shows that regular physical activity is safe for healthy and for frail older people and the risks of developing major cardiovascular and metabolic diseases, obesity, falls, cognitive impairments, osteoporosis and muscular weakness are decreased by regularly completing activities ranging from low intensity walking through to more vigorous sports and resistance exercises. Yet, participation in physical activities remains low amongst older adults, particularly those living in less affluent areas. Older people may be encouraged to increase their activities if influenced by clinicians, family or friends, keeping costs low and enjoyment high, facilitating group-based activities and raising self-efficacy for exercise.
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Context: Age-related hepatic fat accumulation increases the risk of cardiometabolic diseases, and the fibroblast growth factor (FGF) 21-resistant state caused by fatty liver underlies the pathogenesis of these diseases. Objective: Previous studies suggested that a higher level of cardiorespiratory fitness was associated with both lower hepatic fat content and serum FGF21 levels; however, the effect of endurance exercise on hepatic fat content and serum FGF21 concentration has not been studied. Therefore, we aimed to elucidate whether endurance exercise reduced hepatic fat content and serum FGF21 levels. Design: Randomized crossover trial. Setting: Institutional practice. Patients: Thirty-three elderly Japanese men. Intervention: A 5-week endurance exercise program that comprised of three cycle ergometer sessions per week. Main outcome measures: Hepatic fat content was assessed by proton magnetic resonance spectroscopy, and serum FGF21 level was determined by ELISA. Results: A 5-week endurance exercise program decreased the hepatic fat content and serum FGF21 levels without weight loss, and the changes were higher in the exercise period than in the control period (p=0.021 and p=0.026, respectively). Correlation analysis demonstrated that only the change in hepatic fat content was significantly and positively correlated with change in serum FGF21 levels (r=0.366, p=0.006). Conclusions: A 5-week endurance exercise program decreased hepatic fat content and serum FGF21 levels without weight loss in elderly men, and exercise-induced hepatic fat reduction mediated the reduction in serum FGF21 levels. These findings suggest that endurance exercise modulates hepatic fat content and FGF21 resistance, regardless of obesity status.
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Background: The traditional view on the relationship between lipid biomarkers and CVD risk has changed during the last decade. However, it is not clear whether novel lipid biomarkers are able to confer a better predictability of CVD risk, compared to traditional ones.Under this perspective, the aim of the present work was to evaluate the predictive ability of blood lipids' profile on all cause mortality as well as 10-year incidence of CVD, in a sample of apparently healthy adults of the ATTICA epidemiological study. Methods: From May 2001 to December 2002, 1514 men and 1528 women (>18 y) without any clinical evidence of any other chronic disease, at baseline, were enrolled. In 2011-12, the 10-year follow-up was performed in 2583 participants (85 % follow-up participation rate). Incidence of fatal or non-fatal CVD was defined according to WHO-ICD-10 criteria. Baseline serum blood lipids' profile (Total-C, HDL-, non HDL-, LDL-cholesterol, triglycerides (TG), apolipoprotein (Apo)A1 and B, and lipoprotein-(a) levels were also measured. Results: The 10-year all-cause mortality rate was 5.7 % for men and 2.0 % for women (p = 0.55). The, 10-year CVD incidence was 19.7 % in men and 11.7 % in women (p < 0.001). Multi-adjusted analysis revealed that TC, non-HDL-C, TG and TG/HDL-C ratio, were independent predictors of all cause mortality (RR per 1 mg/dL or unit (95 % CI): 1.006 (1.000-1.013), 1.006 (1.000-1.013), 1.002 (1.000-1.004), 1.038 (1.001-1.077), respectively). Moreover, TC, HDL-, LDL-, non-HDL-cholesterol, TG, apoA1, TC/HDL-C and TG/HDL-C were independently associated with CVD risk. Among all lipid indices the ratio of apoB/apoA1 demonstrated the best correct reclassification ability, followed by non-HDL-C and TC/HDL-C ratio (continuous Net Reclassification Index 26.1 and 21.2 %, respectively). Conclusion: Elevated levels of lipid biomarkers are independently associated with all-cause mortality, as well as CVD risk. The ratio of apoB/apoA1, followed by non-HDL-C, demonstrated the best correct classification ability of the developed CVD risk models.
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We investigated whether a training protocol that involved 3 min of intense intermittent exercise per week — within a total training time commitment of 30 min including warm up and cool down — could increase skeletal muscle oxidative capacity and markers of health status. Overweight/obese but otherwise healthy men and women (n = 7 each; age = 29±9 y; BMI = 29.8±2.7 kg/m2) performed 18 training sessions over 6 wk on a cycle ergometer. Each session began with a 2 min warm-up at 50 W, followed by 3×20 s “all-out” sprints against 5.0% body mass (mean power output: ∼450–500 W) interspersed with 2 min of recovery at 50 W, followed by a 3 min cool-down at 50 W. Peak oxygen uptake increased by 12% after training (32.6±4.5 vs. 29.1±4.2 ml/kg/min) and resting mean arterial pressure decreased by 7% (78±10 vs. 83±10 mmHg), with no difference between groups (both p<0.01, main effects for time). Skeletal muscle biopsy samples obtained before and 72 h after training revealed increased maximal activity of citrate synthase and protein content of cytochrome oxidase 4 (p<0.01, main effect), while the maximal activity of β-hydroxy acyl CoA dehydrogenase increased in men only (p<0.05). Continuous glucose monitoring measured under standard dietary conditions before and 48–72 h following training revealed lower 24 h average blood glucose concentration in men following training (5.4±0.6 vs. 5.9±0.5 mmol/L, p<0.05), but not women (5.5±0.4 vs. 5.5±0.6 mmol/L). This was associated with a greater increase in GLUT4 protein content in men compared to women (138% vs. 23%, p<0.05). Short-term interval training using a 10 min protocol that involved only 1 min of hard exercise, 3x/wk, stimulated physiological changes linked to improved health in overweight adults. Despite the small sample size, potential sex-specific adaptations were apparent that warrant further investigation.
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High intensity training (HIT) is effective at improving health; however, it is unknown whether HIT also improves physical function. This study aimed to determine whether HIT improves metabolic health and physical function in untrained middle aged individuals. Fourteen (three male and eleven female) untrained individuals were recruited (control group n = 6: age 42 ± 8 y, weight 64 ± 10 kg, BMI 24 ± 2 kg·m-2 or HIT group n = 8: age 43 ± 8 y, weight 80 ± 8 kg, BMI 29 ± 5 kg·m-2). Training was performed twice weekly, consisting of 10 × 6-second sprints with a one minute recovery between each sprint. Metabolic health (oral glucose tolerance test), aerobic capacity (incremental time to exhaustion on a cycle ergometer) and physical function (get up and go test, sit to stand test and loaded 50 m walk) were determined before and after training. Following eight weeks of HIT there was a significant improvement in aerobic capacity (8% increase in VO2 peak; p < 0.001), physical function (11%-27% respectively; p < 0.05) and a reduction in blood glucose area under the curve (6% reduction; p < 0.05). This study demonstrates for the first time the potential of HIT as a training intervention to improve skeletal muscle function and glucose clearance as we age.
Unlabelled: The accepted model of autonomic control of heart rate (HR) during dynamic exercise indicates that the initial increase is entirely attributable to the withdrawal of parasympathetic nervous system (PSNS) activity and that subsequent increases in HR are entirely attributable to increases in cardiac sympathetic activity. In the present review, we sought to re-evaluate the model of autonomic neural control of HR in humans during progressive increases in dynamic exercise workload. We analysed data from both new and previously published studies involving baroreflex stimulation and pharmacological blockade of the autonomic nervous system. Results indicate that the PSNS remains functionally active throughout exercise and that increases in HR from rest to maximal exercise result from an increasing workload-related transition from a 4 : 1 vagal-sympathetic balance to a 4 : 1 sympatho-vagal balance. Furthermore, the beat-to-beat autonomic reflex control of HR was found to be dependent on the ability of the PSNS to modulate the HR as it was progressively restrained by increasing workload-related sympathetic nerve activity. In conclusion: (i) increases in exercise workload-related HR are not caused by a total withdrawal of the PSNS followed by an increase in sympathetic tone; (ii) reciprocal antagonism is key to the transition from vagal to sympathetic dominance, and (iii) resetting of the arterial baroreflex causes immediate exercise-onset reflexive increases in HR, which are parasympathetically mediated, followed by slower increases in sympathetic tone as workloads are increased.