ArticlePDF Available

Hourly 4-s Sprints Prevent Impairment of Postprandial Fat Metabolism from Inactivity


Abstract and Figures

High postprandial plasma lipids (PPL; i.e., triglycerides) are a risk factor for cardiovascular disease. Physical inactivity, characterized by prolonged sitting and a low step count, elevates PPL and thus risk of disease. Purpose: This study determined if the interruption of prolonged sitting (i.e., 8 h of inactivity) with hourly cycling sprints of only 4-s duration each (i.e., 4 s × 5 per hour × 8 h = 160 s·d SPRINTS) improves PPL. The 4-s sprints used an inertial load ergometer and were followed by 45 s of seated rest. Methods: Four men and four women participated in two trials. Interventions consisted of an 8-h period of sitting (SIT), or a trial with equal sitting time interrupted with five SPRINTS every hour. The morning after the interventions, PPL and fat oxidation were measured over a 6-h period. Plasma glucose, insulin, and triglyceride concentrations were measured bihourly and incremental area under the curve (AUC) was calculated. Results: No differences (P > 0.05) between interventions were found for plasma insulin or glucose AUC. However, SPRINTS displayed a 31% (408 ± 119 vs 593 ± 88 mg·dL per 6 h; P = 0.009) decrease in plasma triglyceride incremental AUC and a 43% increase in whole-body fat oxidation (P = 0.001) when compared with SIT. Conclusions: These data indicate that hourly very short bouts (4 s) of maximal intensity cycle sprints interrupting prolonged sitting can significantly lower the next day's postprandial plasma triglyceride response and increase fat oxidation after a high-fat meal in healthy young adults. Given that these improvements were elicited from only 160 s of nonfatiguing exercise per day, it raises the question as to what is the least amount of exercise that can acutely improve fat metabolism and other aspects of health.
Content may be subject to copyright.
Downloaded from by J7saZb2BtFWtEFTE/FWqiYrARdD5zLW7px51m+r71HoiI/ss8HfA/WOG110HYwvCuowPM/LxAV64My/eBB1kupWuJrXEqPXzgASjbdI5TqOr5Rn3sfnQOR2O3iIOXFG6 on 09/14/2020
Downloadedfrom by J7saZb2BtFWtEFTE/FWqiYrARdD5zLW7px51m+r71HoiI/ss8HfA/WOG110HYwvCuowPM/LxAV64My/eBB1kupWuJrXEqPXzgASjbdI5TqOr5Rn3sfnQOR2O3iIOXFG6 on 09/14/2020
Hourly 4-s Sprints Prevent Impairment of
Postprandial Fat Metabolism from Inactivity
Human Performance Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX
WOLFE, A. S., H. M. BURTON, E. VARDARLI, and E. F. COYLE. Hourly 4-s Sprints Prevent Impairment of Postprandial Fat Metabolism
from Inactivity. Med. Sci. Sports Exerc., Vol. 52, No. 10, pp. 22622269, 2020. High postprandial plasma lipids (PPL; i.e., triglycerides) are a
risk factor for cardiovascula r disease. Physical inactivity, characterized by prolonged s itting and a low step count, elevates PPL and thus risk of
disease. Purpose: This study determined if the interruption of prolonged sitting (i.e., 8 h of inactivity) with hourly cycling sprints of only 4-s
duration each (i.e., 4 s 5perhour8h=160s·d
SPRINTS) improves PPL. The 4-s sprints used an inertial load ergometer and were
followed by 45 s of seated rest. Methods: Four men and four women participated in two trials. Interventions consisted of an 8-h period of
sitting (SIT), or a trial with equal sitting time interrupted with five SPRINTS every hour. The morning after the interventions, PPL and fat
oxidation were measured over a 6-h period. Plasma glucose, insulin, and triglyceride concentrations were measured bihourly and incremental
area under the curve(AUC) was calculated. Results: No differences (P> 0.05) between interventions were found for plasma insulin or glucose
AUC. However, SPRINTS displayed a 31% (408 ± 119 vs 593 ± 88 mg·dL
per 6 h; P= 0.009) decrease in plasma triglyceride incremental
AUC and a 43% increase inwhole-body fat oxidation (P= 0.001) when compared with SIT.Conclusions: These data indicate that hourly very
short bouts (4 s) of maximal intensity cycle sprints interrupting prolonged sitting can significantly lower the next days postprandial plasma
triglyceride response and increase fat oxidation after a high-fat meal in healthy youngadults. Given that these improvements were elicitedfrom
only 160 s of nonfatiguing exercise per day, it raises the question as to what is the least amount of exercise that can acutely improve fat me-
tabolism and other aspects of health. Key Words: PROLONGED SITTING, LIPEMIA, INERTIAL LOAD ERGOMETER
Over the past several decades, people living in modern
societies have become more and more physically in-
active because of technological innovations that have
greatly increased screen timeand reduced the need to move
(13). As a result, people are spending an increasing amount
of time sitting throughout the waking hours, and they are
doing so with long periods that are devoid of meaningful
physical activity. Physical inactivity impairs cardiometa-
bolic health, and it is estimated to cause 16% of all deaths,
largely through cardiovascular disease (24).
The identification of effective activity/exercise programs to
counteractperiods of inactivity from prolonged sitting is ongo-
ing. One alarming statistic indicates that people who meet the
recommended level of exercise (i.e., 150 min·wk
of moder-
ate intensity [5,6]) are still at elevated risk of cardiovascular
disease if they sit for prolonged periods throughout the day
(24). A large epidemiological study (3), estimated that in
order to counteract the effects of prolonged sitting, a person
needs to exercise for 6075 min·d
at moderate intensity. Fur-
thermore, recent work by Kim et al. (7) and Akins et al. (8) re-
ported that 60 min of running (e.g., 63%67% V
to improve postprandial lipemia after several days of sitting for
13.5 h·d
, a condition termed exercise resistance.There-
fore, it seems impractical to explore exercise bouts of longer
than 1 h·d
to counteract the cardiometabolic risk of pro-
longed sitting due to adherence problems in the general popu-
lation. Furthermore, the main reason people give for being
inactive is lack of time to move and/or exercise throughout
the day (9).
Another approach is to interrupt prolonged sitting with peri-
odic bouts of activity/exercise throughout the day. Walking for
13 min every 1530 min has been found to improve post-
prandial glucose metabolism on the day of the 1- to 3-min
bouts, yet it did not improve postprandial lipemia (1012).
However, a recent study using the same protocol found post-
prandial lipemia to be improved the next day, agreeing with
the idea that it takes 1224 h for the effects of activity/
exercise to be manifested in improved lipid metabolism (13).
Given that people claim a major reason for not being phys-
ically active or exercising is lack of time (9), it follows that a
mode of exercise, which is as brief as possible, should be in-
vestigated. Very brief exercise performed with maximal effort
has the advantage of being capable of producing very-high-
power outputs and thus activation of a large mass of muscle.
When sprints are performed maximally, both type I and type
Address for correspondence: Edward F. Coyle, Ph.D., Human Performance
Laboratory, Department of Kinesiology and Health Education, University
of Texas at Austin, One University Station, Austin, TX 78712; E-mail:
Submitted for publication July 2019.
Accepted for publication March 2020.
Copyright © 2020 by the American College of Sports Medicine
DOI: 10.1249/MSS.0000000000002367
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
II muscle fibers are activated, and when the duration is very
short (i.e., 4 s), there is little fatigue, thus allowing multiple
sprints to be performed with 30- to 45-s rest in between sprints.
This study sought to determine if very brief (4-s) cycling
performed at maximal intensity in blocks of five repetitions
per hour is effective in counteracting the effects of prolonged
sitting on postprandial lipid metabolism. In the control trial,
subjects sat for 8 h and postprandial metabolism was measured
the next day (SIT). This was compared with an exercise trial of
repeated (5) cycling sprints lasting only 4 s each, performed
every hour for 8 h (SPRINTS). Sprints were performed on an
inertial load ergometer (ILE) (14). Therefore, each hour, only
20 s of sprint exercise was performed and only 160 s of
SPRINTS was performed for the entire day.
Subjects. Eight healthy, untrained to recreationally active
men (n= 4) and women (n= 4) were recruited to participate in
this study. Subject characteristics can be seen in Table 1. Sub-
jects were given written and verbaldescription of all the proce-
dures and measurements used in this study, and written
informed consent was obtained. The institutional review board
of the University of Texas at Austin approved this study
( Identifier: NCT03856606).
Research protocol. All subjects completed two trials in
a randomized crossover design, with each trial occurring over
4 d with a minimum of 7 d between trials (Fig. 1). The first 2 d
of each trial served as a control period allowing for familiari-
zation and the control of physical activity and calorie con-
sumption before the intervention. After each control period,
subjects then performed one of the interventions on day 3.
The interventions consisted of either 8 h of prolonged sitting
(SIT) or 8 h of sitting interrupted every hour by five sprints
lasting 4 s each using the ILE (SPRINTS). The sitting time
of the trials was not different. The sprint on the ILE involves
accelerating a flywheel with a known inertia from zero
TABLE 1. Subject characteristics (n=8;4menand4women).
Characteristic Mean ± SEM Male (n=4) Female(n=4)
Age (yr) 24.0 ± 1.8 26.0 ± 2.4 22.0 ± 2.1
Height (cm) 169.0 ± 4.6 176.8 ± 6.1 161.1 ± 2.6
Body mass (kg) 70.9 ± 6.0 81.3 ± 8.0 60.4 ± 3.1
BMI (kg·m
) 24.5 ± 0.8 25.8 ± 1.0 23.2 ± 0.6
RMR (kcal·d
) 1727 ± 210 20,367 ± 329 1418 ± 95
FIGURE 1Representation of experimental design. During SIT trial, subjects remained seated for 8 h, only getting up for the restroom and to prepare
food. For the SPRINTS trial, subjects spent the same time seated, only getting up for the restroom and food. However, at the end of each hour, they per-
formed five maximal sprints lasting 4 s in duration using the ILE (SPRINTS).
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
velocity to the highest RPM possible in approximately 4 s.
Power per revolution of the cycle is calculated as the product
of flywheel inertia and gearing, acceleration, and velocity (14).
Controlled activity phase. During the 2-d controlled ac-
tivity phase, subjects were asked to arrive at the laboratory at
approximately 0900 h. Subjects were instructed to take be-
tween 5000 and 7500 steps per day, which is approximately
equal to a nonsedentary, low physical activity step count (15).
Subjects were then equipped with an activPAL activity moni-
tor (activPAL, PAL Technologies, Glasgow, Scotland) to be
secured onto a thigh for the assessment of body position and
movement. Steps taken were not visible to the subjects,
whereas the device was being worn; therefore, subjects were
also asked to download a pedometer application on their
mobile phones to provide visual feedback for daily step
count. Subjects were also asked to refrain from exercise
and to record all food intake and to minimize physical activ-
ity. They were then asked to repeat this diet and activity for
the remaining trial.
Intervention phase. During the SIT trial, subjects re-
mained seated for 8 h with the ability to get up for food and
restroom usage. Estimates of the caloric intake were determined
from preliminary tests of resting metabolic rate (RMR) and the
addition of approximately 20% for the energy needed for the re-
spective daily activity and maintenance of a stable body weight.
Adherence to these guidelines was checked against the pedome-
ter and activPAL, and food journals were analyzed to ensure par-
ticipants duplicated their diet for the duration of the two trials.
During the SPRINTS trial, subjects were asked to report to
the laboratory at 0900 h to begin the 8-h prolonged sit,
interrupted by ILE sprints. During the prolonged sit and during
the final 4 min of each hour, subjects performed five 4-s
sprints separated by 45 s of rest, equating to 20 s of exercise
per hour and 160 s of total time exercising on the SPRINT
day. Given that each set of five SPRINTS required approxi-
mately 5 min to complete when resting for 45 s between
SPRINTS and the fact that eight sets were completed, the total
daily time required was 40 min. During the rest periods be-
tween sprints, subjects were seated. RPE was taken after five
sprints using the standard Borg Scale (620). Food was pro-
vided at two times (lunch and dinner) over the duration of
the trial, and the caloric content of these meals was such that
energy balance was maintained.
High-fat/glucose tolerance test phase. The morning
after each intervention day, subjects were asked to arrive to the
laboratory to begin the high-fat/glucose tolerance test (HFGTT).
Subjects remained seated for the 6-h duration of the test except
for restroom usage. After a 5-min acclimatization period, a fasted
blood sample was obtained via antecubital venous puncture into
a 4-mL K2 EDTA vacutainer (BD Vacutainer; Fischer Scien-
tific, Hampton, NH), and plasma was subsequently aliquoted
into a microcentrifuge tube, labeled, and stored at 80°C for
future batch analysis. This process was repeated for blood
samples obtained 2, 4, and 6 h postprandially.
Subjects were asked to ingest a high-fat and carbohydrate
shake, afterwhich blood was sampled as described previously.
breathe into a meteorological balloon for a total of 15 min to
monitor fat oxidation and metabolic rate. Subject body mass
was taken by a digital scale (Ohaus, CW-11, Parsippany, NJ)
and recorded to the nearest 0.5 kg, and height was measured
using a standard stadiometer.
Blood sampling and analysis. After the collection into
K2 EDTA tubes, blood was subsequently centrifuged at
3000 rpm at 4°C for 10 min. Plasma was then aliquoted and
frozen at 80°C and later analyzed for triglyceride, glucose,
and insulin concentrations. Triglyceride was measured using
a spectrophotometric method from commercially available
kits (Pointe Scientific, Inc., Canton, MI). Glucose was mea-
sured using a similar protocol from commercially available
kits (Pointe Scientific). Plasma insulin was measured using a
microplate reader and commercially available kits (LDN Im-
munoassays and Services, Nordhorn, Germany). Coefficients
of variation for triglyceride, glucose, and insulin were 3.0%,
3.5%, and 4.9% respectively.
Diet control. The caloric content was roughly ~20%
higher than each subjects RMR, as measured during prelimi-
nary testing. Additional energy expenditure from exercise in
the SPRINTS was estimated via indirect calorimetry. The
postexercise meals were approximately 60% carbohydrate,
20% fat, and 20% protein. For the HFGTT, subjects were pro-
vided with a high-fat shake consisting of parts melted ice
cream and heavy whipping cream, creating a macronutrient
and caloric profile of 1.34 g·kg
fat, 0.92 g·kg
drate, 0.19 g·kg
protein, and 16.5 kcal·kg
RMR and indirect calorimetry. All metabolic gas mea-
surements were made using meteorological balloons. To de-
termine RMR, subjects rested in a seated position for 15 min,
followed by a 15-min period of gas collection. Subjects
breathed through a one-way valve (Hans Rudolph, Kansas
City, MO) directly attached to a meteorological balloon. A
sample was then analyzed for concentrations of O
and N
by mass spectrometry (PerkinElmer MGA 1100, St.
Louis, MI). Gas volume was then measured via spirometry
(Vacumed, Ventura, CA). During each HFGTT, gas samples
were analyzed following the procedures detailed previously
at 0, 2, 4, and 6 h after shake ingestion for calculation of fat
and carbohydrate oxidation rate, using the tables of Frayn (16).
Statistical analysis. Incremental (AUC
) and total area
under the curve (AUC
) for concentrations of plasma triglyc-
eride, insulin, and glucose were calculated. Once calculated,
Student t-test with Bonferroni correction was used to test for
differences. Plasma insulin, glucose, and triglyceride concen-
trations were analyzed using repeated-measures two-way
ANOVA (trialtime). Likewise, daily step count and hourly
distribution of posture were analyzed using repeated-
measures two-way ANOVAs. Lastly, fasting and postprandial
RER, as well as fat and carbohydrate oxidation, were analyzed
using a repeated-measure two-way ANOVA. When interac-
tions were significant, Tukey honest significant difference
post hoc tests were run. Effect sizes were calculated as mean
http://www.acsm-msse.org2264 Official Journal of the American College of Sports Medicine
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
differences divided by the pooled SD (Cohen d); quantitative
criteria for effect sizes used to explain practical significance of
the findings were taken from Cohen (17). With eight partici-
pants, the study had 68% power to detect a difference of 1.0
SD (i.e., Cohen d= 1.0) between conditions.
All data were analyzed using GraphPad Prism 7 (GraphPad
Software Inc., La Jolla, CA). All data are expressed as
mean ± SEM; unless otherwise noted, the level for statistical
significance was set at P<0.05.
Daily steps and body posture. No significant differ-
ences were found comparing trials in daily steps, for C1, C2,
or the intervention day (Table 2). The average number of steps
taken on the intervention day was low (i.e., 3577 ± 953 and
2540 ± 969 for SPRINTS and SIT), respectively (P=0.34).
There were no significant differences between the groups for
time spent sitting (P= 0.81) or time spent standing (P=0.86).
Furthermore, the caloric intake on the intervention day was sim-
ilar for SPRINTS and SIT (2065 ± 235 and 2068 ± 232 kcal),
respectively (P=0.66).
Response to inertial load ergometry. During the
SPRINTS trial, the average power generated by the 4-s sprints
was 870 ± 139 W (male, 1107 ± 447 W; female, 632 ± 90 W)
and RPE remained low (10.0 ± 0.7; very to fairly light).
Plasma triglyceride glucose and insulin responses.
Postprandial plasma triglyceride responses are shown in
Figure 2. There was a 31% reduction in incremental AUC
ing the 6-h period in SPRINTS as compared with the SIT trial
(408 ± 119 vs 593 ± 88 mg·dL
and a medium effect size (d= 0.632). However, total AUC
for plasma triglyceride did not reach significance between trials
(SPRINTS: 858 ± 154 mg·dL
vs SIT: 1003 ± 136 mg·dL
P= 0.11; Table 3). There were no significant differences be-
tween trials in the postprandial plasma glucose total AUC
(SPRINTS: 678 ± 49 mg·dL
vs SIT: 707 ± 32 mg·dL
P= 0.66) or incremental AUC
(SPRINTS: 150 ± 36 mg·dL
SIT: 159 ± 28 mg·dL
;P= 0.88; Fig. 2; Table 3). Further-
more, there were no differences in insulin responses between
trials in total AUC
(SPRINTS: 157 ± 16 μIU·mL
vs SIT:
159 ± 12 μIU·mL
;P= 0.92) or incremental AUC
(SPRINTS: 85 ± 10 μIU·mL
vs SIT: 73 ± 11 μIU·mL
P= 0.46; Fig. 2; Table 3).
Postprandial substrate oxidation. RER demonstrated
both a significant trial effect (P= 0.001) and main effect of
time (P= 0.02) but no interaction between the two, and exhib-
ited a large effect size (d= 1.16 ± 0.04; Table 4). The average
grams of fat oxidized over the 6-h period of the HFGTT was
43% higher (P< 0.001) during SPRINTS versus SIT (SPRINTS:
TABLE 2. Daily step count and hours per day spent sitting/supine and standing in SIT or
Day of Trial
Control Day 1 Control Day 2 Intervention Day
Daily Steps (steps per day)
SIT 6889 ± 1249 6626 ± 1111 2540 ± 969
SPRINTS 7249 ± 1264 6537 ± 1198 3577 ± 954
Distribution of posture (h·d
SIT 12.6 ± 0.7 12.7 ± 0.8 15.2 ± 0.5
SPRINT 12.7±1.1 12.7±0.8 14.9±0.4
SIT 2.7±0.5 2.7±0.6 0.8±0.2
SPRINTS 2.8±0.8 3.2±0.5 1.0±0.2
The controldays represent normal physical activity, and on the intervention day, sitting time
was increased and steps per day were reduced.
Significantly different from control days by design.
FIGURE 2Postprandial plasma responses during the HFGTT. Plasma
triglyceride concentration (A), plasma glucose concentration (B), and
plasma insulin concentration (C).
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
48.9 ± 17.7 g vs SIT: 34.1 ± 18.2 g; Table 4). Conversely, car-
bohydrate oxidation was significantly lower (P=0.002)in
SPRINTS versus SIT (SPRINTS: 13.0 ± 10.2 g vs SIT:
44.2 ± 22.3 g; Table 4).
This study reports the effects of interrupting prolonged sit-
ting with brief (4-s) maximal intensity cycling sprints on post-
prandial fat and carbohydrate metabolism measured the
following day. This investigations major finding was that
hourly maximal intensity 4-s sprints (performed five times
per hour) on an ILE (SPRINTS) while sitting for 8-h reduced
the next days postprandial plasma triglyceride incremental
AUC by 31% (P= 0.009) compared with sitting for 8 continuous
hours (SIT). Furthermore, SPRINTS significantly (P= 0.001) el-
evated fat oxidation by an average of 43% over the duration of
HFGTT corresponding to a large effect size increase compared
with SIT. This investigation did not use techniques that might
determine if the two phenomena are causally related, yet it is
possible that the postprandial lowering of plasma triglyceride
concentration was due to increased tissue uptake and oxida-
tion of the ingested plasma triglycerides.
When subjectswho are physicallyactive and taking approx-
imately >8000 steps per day add a 1-h bout of running or a ses-
sion of high-intensity interval training to their regime, they
show an improvement in their next days postprandial plasma
triglyceride response as well as increased fat oxidation
(1820). This can be considered the healthy exercise re-
sponse.However, in people who are largely sedentary (i.e.,
20004000 steps per day) (15), a 1-h bout of running does
notimprovethenextdays postprandial plasma triglyceride
response or fat oxidation (7,8). This has been termed exer-
cise resistance, as it seems that some aspect of the prolonged
inactivity is preventing the acute bout of exercise from caus-
ing healthy adaptations in fat metabolism (7,8). In the pres-
were taking <4000 steps per day and thus sedentary, outside
of the 160 s of exercise in SPRINTS. It is likely that the
hourly sprints prevented exercise resistance from occurring
and that is the reason for the enhanced fat metabolism in
SPRINTS compared with SIT. The time course with which
exercise resistance occurs from inactivity is unknown, but it
seems that the present 20 s of hourly intermittent sprints,
performed maximally in five bouts of 4 s each, was effective
in counteracting it.
The hourly set of five sprints lasting 4 s each, with 45 s of
rest, describes an exercise that is predominantly anaerobic, re-
lying heavily on stores of ATP and PC for energy during exer-
cise and oxidative metabolism for resynthesis of these stores
during recovery (21). Given that the sprints elicited maximal
power and involved maximal acceleration to an RPM of
120160, the recruitment of both type I and type II muscle
fibers should have reached maximal levels. It is likely that
some aspect of high motor unit recruitment producing very
high anaerobic power was responsible for the effectiveness
of SPRINTS for enhancing fat metabolism (7,8). This is sur-
prising in that fat oxidation is aerobic and it might be thought
that aerobic exercise would be its specific stimulator. What
seems to be truly different about the SPRINTS exercise is
the high average maximal power (870 ± 139 W) and assumed
type II fiber recruitment. Furthermore, perceived exertion was
very to fairly light(10.0 ± 0.7) because of the only 4-s dura-
tion of each sprint and relatively long recovery period (45 s).
Overall, the maximal intensity sprints of 4-s duration are a rel-
atively nonfatiguing method of activating a large quantity of
muscle, and it seems that fat oxidation is improved on the fol-
lowing day.
It is not clear why the present investigation observed an
amelioration of postprandial lipemia when others, who also
broke up prolonged sitting, did not (10,11). However,
TABLE 3. Mean ± SE values for postprandial AUC responses over the 6-h postprandial
Incremental AUC
Triglyceride (mg·dL
6h) 593±88 408±119
Glucose (mg·dL
6h) 159±81 150±103
Insulin (μIU·mL
6 h) 72.7 ± 31 84.9 ± 28
Total AUC
Triglyceride (mg·dL
6 h) 1003 ± 136 858 ± 154
Glucose (mg·dL
6h) 707±91 678±140
Insulin (μIU·mL
6h) 159±33 157±46
SPRINTS significantly lower than SIT (P<0.009).
TABLE 4. Postprandial substrate oxidation in SIT vs SPRINT over the 6-h period.
Hours Postprandial
Hour 0 0.841 ± 0.034 0.752 ± 0.014*
Hour 2 0.839 ± 0.033 0.750 ± 0.018*
Hour 4 0.823 ± 0.044 0.725 ± 0.017*
Hour 6 0.761 ± 0.022 0.709 ± 0.010
Substrate oxidation (%)
Hour 0 52.8 ± 11.1 83.1 ± 4.7**
Hour 2 53.5 ± 11.4 84.2 ± 6.0**
Hour 4 60.3 ± 14.3 90.9 ± 5.2**
Hour 6 79.1 ± 6.94 95.8 ± 3.0
Hour 0 47.3 ± 11.1 16.9 ± 4.7*
Hour 2 46.5 ± 11.4 15.9 ± 6.0*
Hour 4 39.8 ± 14.3 9.1 ± 5.2*
Hour 6 20.9 ± 6.94 4.2 ± 3.0
Substrate oxidation (g·min
Hour 0 0.066 ± 0.016 0.122 ± 0.019**
Hour 2 0.075 ± 0.018 0.119 ± 0.016**
Hour 4 0.102 ± 0.028 0.148 ± 0.022**
Hour 6 0.136 ± 0.023 0.155 ± 0.019
Hour 0 0.145 ± 0.051 0.038 ± 0.018*
Hour 2 0.182 ± 0.055 0.055 ± 0.021*
Hour 4 0.107 ± 0.027 0.027 ± 0.017*
Hour 6 0.057 ± 0.018 0.011 ± 0.008
Energy expenditure (kcal·min
Hour 0 1.19 ± 0.136 1.31 ± 0.168
Hour 2 1.47 ± 0.191 1.35 ± 0.184
Hour 4 1.40 ± 0.165 1.42 ± 0.179
Hour 6 1.49 ± 0.131 1.32 ± 0.127
*SPRINTS different from SIT (P< 0.05).
**SPRINTS different from SIT (P<0.01).
http://www.acsm-msse.org2266 Official Journal of the American College of Sports Medicine
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
improvements in glucose and insulin metabolism have been
typically seen on the day of the intervention and during the
postprandial test, yet the improvement in postprandial lipemia
has been observed the following day (12), which agrees with
our present observations. Although this study did not directly
investigate possible mechanisms, one hypothesis stems from
the dysregulation of lipoprotein lipase (LPL), the rate-
limiting enzyme for chylomicron and VLDL tissue uptake
(22,23). Indeed, prolonged inactivity has been shown to de-
crease LPL activity up to 90% and influence the amount of
heparin releasable LPL (24,25). The primary mechanism be-
hind an attenuation of postprandial lipemia is hypothesized
to be an upregulation of LPL after exercise. LPL activity typ-
ically peaks 8 h after exercise (2628). Thus, it is feasible that
the periodic interruption of sitting and a large amount of mus-
cle fiber activation with SPRINTS prevented a decrease in
LPL activity during the 8-h period of sitting used by this inves-
tigation. It is noteworthy that this might be achieved with only
20 s·h
of exercise, albeit at maximal power.
Previous research has shown that aerobic exercise at 30%
70% of V
with a minimum of ~360950 kcal of energy
expenditure is needed to reduce postprandial lipemia the next
day (18,19,2932). In the present study, participants expended
much less energy with an amount that is below the health
guidelines recommended for energy expenditure (33). How-
ever, a reduction in postprandial lipemia from small amounts
of energy expenditure is not unprecedented, as resistance exer-
cise as well as sprint interval cycling, without caloric replace-
ment, has been shown to cause postprandial lipemia reduction
(3436). The low energy expenditure and low time commit-
ment could be seen as a benefit to SPRINTS type exercise per-
formed for only 4 s, and five times per hour, because the main
reason people give for not exercising is lack of time (9). How-
ever, over the eight sets of hourly sprints of the present design,
the total time involvement amounted to 40 min, which could
be reduced by shortening the recovery period between sprints
or by reducing the number of sets. Using similar test meals and
design, we have shown significant reductions in integrated tri-
glyceride AUC
with 1-h bouts of treadmill running, or cycling
at intensities ranging from 50% to 90% V
(19,20). Kim
et al. (19) found a 27% reduction in the AUC
after running at
65% V
for 1 h. Similar reductions in triglyceride AUC
(i.e., 31%) were seen in the present study with a total exercise
time of only 160 s (2.7 min). The most salient aspect of the ex-
ercise bouts were that each 4-s sprint was performed at true
maximal power output, which in these subjects averaged 870 W.
This maximal power is roughly three to four times the power
needed to elicit maximal oxygen uptake. Indeed, the 4-s sprints,
by eliciting maximal power output, represent the highest possi-
ble rate of muscle fiber recruitment, especially of type II muscle
fibers but without fatigue. This is unlike cycling sprints that last
for 2030-s durations and elicit an extreme accumulation of lac-
tic acid and intense fatigue (37).
The negative health consequences of prolonged sitting and
inactivity are often lumped together because most of the pe-
riods in which people are inactive; they spend sitting and
sometimes standing (38). As a result, it could be thought that
the act of sitting per se is unhealthy compared with other forms
of inactivity. In the present study, the sitting time was the same
in SIT and SPRINTS, given that so little time was spent
exercising in SPRINTS and the recovery time was spent
seated. Our observation that the next days postprandial hyper-
lipemia after 8 h of sitting could be successfully overcome by
physical activity that amounted to only 160 s indicates that sit-
ting may not be inherently negative beyond its inactivity, at
least in terms of postprandial lipemia.
Although the present study adds to the body of literature re-
garding inactivity and postprandial responses, it is not without
limitations. We did not control for phase of menstrual cycle in
the female participants, as it has been previously shown that
postprandial responses vary according to phase of menstrual
cycle (39). This may have influenced the study findings. Fur-
thermore, this study made use of a small number of subjects re-
ducing the statistical power and increasing the likelihood of
type II errors, as such potential differences between trials
may not be fully represented. This also extends to the ability
to detect sex differences within the study design. A previous
quantitative review has suggested that sex may play a role in
acute exercise-induced reductions of postprandial lipemia
(18). In that review, sex was found to be a moderator with
the effect size of the postexercise reductions being larger in fe-
males when compared with males (18). Lastly, this study in-
vestigated a young, lean, and apparently healthy population.
Even within the SIT trial, subjects displayed favorable re-
sponses. It is unclear if SPRINT exercise might improve me-
tabolism in those with a less than favorable metabolic
profile. It might also depend on their level of background
physical activity as reflected in their step count per day (7).
Furthermore, mechanistic theorizing is beyond the scope of
this study, as it was not designed to determine a mechanism
as to how SPRINTS affect postprandial responses, rather if
such a low volume of exercise could provide an impact.
In conclusion, these data indicate that hourly, maximal ef-
fort, 4-s sprints on an ILE, which interrupts prolonged sitting,
lowers postprandial incremental plasma triglyceride concen-
tration by 31% (P= 0.009) and simultaneously increases fat
oxidation by an average of 43% (P< 0.001) during the next
day. This is particularly significant when considering the small
amount of energy expended, the low RPE reported by the sub-
jects, and the minimal amount of time spent exercising
(160 sd
). The brief nature and nonfatiguing aspect of the ex-
ercise might lead to better adherence when compared with cur-
rent exercise recommendations (6). The clinical significance
of these findings is centered on reductions in postprandial tri-
glyceride incremental AUC and increased fat oxidation, which
likely lead to improved cardiometabolic health.
We thank the subjects for their participation. As a matter of financial
interest disclosure, E. F. Coyle owns equity in Sports Texas Nutri-
tion Training and Fitness, Inc., a company that sells the inertial
load ergometer used in this study. The results of this study do
not constitute endorsement by the American College of Sports
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
A. S. W. and E. F. C. conceived the research and designed the experi-
prep ared fig ures, performed statistical analyses, and drafted the manuscript;
A. S. W., H. M. B., E. V., and E. F.C. edited and revised the manuscript;
A. S. W., H. M. B., E. V., and E. F. C. approved the final version of the manuscript.
The results are presented clearly, honestly, and without fabrication,
falsification, or inappropriate data manipulation.
1. Owen N, Healy GN, Matthews CE, Dunstan DW. Too much sitting:
the population-health science of sedentary behavior. Exerc Sport Sci
2. Patel AV, Bernstein L, Deka A, et al. Leisure time spent sitting in re-
lation to total mortality in a prospective cohort of US adults. Am J
Epidemiol. 2010;172(4):41929.
3. Ekelund U, Steene-Johannessen J, Brown WJ, et al. Does physical
activity attenuate, or even eliminate, the detrimental association
of sitting time with mortality? A harmonised meta-analysis of data
from more than 1 million men and women. Lancet. 2016;388(10051):
4. Biswas A, Oh PI, Faulkner GE, et al. Sedentary time and its associa-
tion with risk for disease incidence, mortality, and hospitalization in
adults: a systematic review and meta-analysis. Ann Intern Med.
5. Garber CE, Blissmer B, Deschenes MR, et al. American College of
Sports Medicine Position Stand. Quantity and quality of exercise
for developing and maintaining cardiorespiratory, musculoskeletal,
and neuromotor fitness in apparently healthy adults: guidance for pre-
scribing exercise. Med Sci Sports Exerc. 2011;43(7):133459.
6. Piercy KL, Troiano RP, Ballard RM, et al. The physical activity
guidelines for Americans. JAMA. 2018;320(19):20208.
7. Kim IY, Park S, Chou TH,Trombold JR, Coyle EF. Prolonged sitting
negatively affects the postprandial plasma triglyceride-lowering
effect of acute exercise. Am J Physiol Endocrinol Metab. 2016;
8. Akins JD, Crawford CK, Burton HM, Wolfe AS, Vardarli E, Coyle
EF. Inactivity induces resistance to the metabolic benefits following
acute exercise. J Appl Physiol. 2019;126(4):108894.
9. Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of
adultsparticipation in physical activity: review and update. Med
Sci Sports Exerc. 2002;34(12):19962001.
10. Dunstan DW, Kingwell BA, Larsen R, et al. Breaking up prolonged
sitting reduces postprandial glucose and insulin responses. Diabetes
Care. 2012;35(5):97683.
11. Larsen RN, Kingwell BA, Robinson C, et al. Breaking up of pro-
longed sitting over three days sustains, but does not enhance, lower-
ing of postprandial plasma glucose and insulin in overweight and
obese adults. Clin Sci (Lond). 2015;129(2):11727.
12. Peddie MC, Bone JL, Rehrer NJ, Skeaff CM, Gray AR, Perry TL.
Breaking prolonged sitting reduces postprandial glycemia in healthy,
normal-weight adults: a randomized crossover trial. Am J Clin Nutr.
13. Homer AR, Fenemor SP, Perry TL, et al. Regular activity breaks
combined with physical activity improve postprandial plasma triglyc-
eride, nonesterified fatty acid, and insulin responses in healthy, nor-
mal weight adults: a randomized crossover trial. JClinLipidol.
2017;11(5):126879. e1.
14. Martin JC, Wagner BM, Coyle EF. Inertial-load method determines
maximal cycling power in a single exercise bout. Med Sci Sports
Exerc. 1997;29(11):150512.
15. Tudor-Locke C, Bassett DR Jr. How many steps/day are enough?
Preliminary pedometer indices for public health. Sports Med. 2004;
16. Frayn KN. Calculation of substrate oxidation rates in vivo from gas-
eous exchange. J Appl Physiol Respir Environ Exerc Physiol. 1983;
17. Cohen J. Statistical Power Analysis for the Behaviors Science. 2nd ed.
Hillsdale (NJ): Laurence Erlbaum Associates; 1988. pp. 202.
18. Freese EC, Gist NH, Cureton KJ. Effect of prior exercise on postpran-
dial lipemia: an updated quantitative review. J Appl Physiol (1985).
19. Kim IY, Park S, Trombold JR, Coyle EF. Effects of moderate- and
intermittent low-intensity exercise on postprandial lipemia. Med Sci
Sports Exerc. 2014;46(10):188290.
20. Trombold JR, Christmas KM, Machin DR, Kim IY, Coyle EF. Acute
high-intensity endurance exercise is more effective than moderate-
intensity exercise for attenuation of postprandial triglyceride eleva-
tion. J Appl Physiol (1985). 2013;114(6):792800.
21. Casey A, Constantin-Teodosiu D, Howell S, Hultman E, Greenhaff
PL. Metabolic response of type I and II muscle fibers during re-
peated bouts of maximal exercise in humans. Am J Physiol. 1996;
271(1 Pt 1):E3843.
22. Bjorkegren J, Packard CJ, Hamsten A, et al. Accumulation of large
very low density lipoprotein in plasma during intravenous infusion
of a chylomicron-like triglyceride emulsion reflects competition for
a common lipolytic pathway. JLipidRes. 1996;37(1):7686.
23. Ginsberg HN, Zhang YL, Hernandez-Ono A. Regulation of plasma
triglycerides in insulin resistance and diabetes. Arch Med Res.
24. Bey L, Hamilton MT. Suppression of skeletal muscle lipoprotein
lipase activity during physical inactivity: a molecular reason to
maintain daily low-intensity activity. JPhysiol. 2003;551(2):
25. Zderic TW, Hamilton MT. Physical inactivity amplifies the sensitiv-
ity of skeletal muscle to the lipid-induced downregulation of lipopro-
tein lipase activity. J Appl Physiol. 2006;100(1):24957.
26. Seip RL, Angelopoulos TJ, Semenkovich CF. Exercise in-
duces human lipoprotein lipase gene expression in skeletal
muscle but not adipose tissue. Am J Physiol. 1995;268(2 Pt 1):
27. Seip RL, Mair K, Cole TG, Semenkovich CF. Induction of hu-
man skeletal muscle lipoprotein lipase gene expression by
short-ter m exercise is transient. Am J Physiol. 1997;272(2 Pt 1):
28. Seip RL, Semenkovich CF. Skeletal muscle lipoprotein lipase: mo-
lecular regulation and physiological effects in relation to exercise.
Exerc Sport Sci Rev. 1998;26:191218.
29. Gill JM, Hardman AE. Postprandial lipemia: effects of exercise and
restriction of energy intake compared. Am J Clin Nutr. 2000;71(2):
30. Herd SL, Kiens B, Boobis LH, Hardman AE. Moderate exercise,
postprandial lipemia, and skeletal muscle lipoprotein lipase activity.
Metabolism. 2001;50(7):75662.
31. Malkova D, Evans RD, Frayn KN, Humphreys SM, Jones PR,
Hardman AE. Prior exercise and postprandial substrate extraction
across the human leg. Am J Physiol Endocrinol Metab. 2000;
32. Silvestre R, Kraemer WJ, Quann EE, et al. Effects of exercise at dif-
ferent times on postprandial lipemia and endothelial function. Med
Sci Sports Exerc. 2008;40(2):26474.
33. Pate RR, Pratt M, Blair SN, et al. Physical activity and public health.
A recommendation from the Centers for Disease Control and Preven-
tion and the American College of Sports Medicine. JAMA. 1995;
34. Pafili ZK, Bogdanis GC, Tsetsonis NV, Maridaki M. Postprandial
lipemia 16 and 40 hours after low-volume eccentric resistance exer-
cise. Med Sci Sports Exerc. 2009;41(2):37582.
http://www.acsm-msse.org2268 Official Journal of the American College of Sports Medicine
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
35. Petitt DS, Arngrimsson SA, Cureton KJ. Effect of resistance
exercise on postprandial lipemia. J Appl Physiol. 2003;94(2):
36. Freese EC, Levine AS, Chapman DP, Hausman DB, Cureton KJ. Ef-
fects of acute sprint interval cycling and energy replacement on post-
prandial lipemia. J Appl Physiol. 2011;111(6):15849.
37. Gibala MJ, McGee SL, Garnham AP, Howlett KF, Snow RJ, Hargreaves
M. Brief intense interval exercise activates AMPK and p38 MAPK
signaling and increases the expression of PGC-1alpha in human skel-
etal muscle. J Appl Physiol (1985). 2009;106(3):92934.
38. Hadgraft NT, Healy GN, Owen N, et al. Office workersobjectively
assessed total and prolonged sitting time: individual-level correlates
and worksite variations. Prev Med Rep. 2016;4:18491.
39. Gill J, Malkova D, Hardman A. Reproducibility of an oral fat toler-
ance test is influenced by phase of menstrual cycle. Horm Metab
Res. 2005;37(5):33641.
Copyright © 2020 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
... 。然而,传统运动由于其在环境、器材、时间和能力等方 面的特定要求,往往难以被大众人群接受或坚持 [4] 。例如:以高效著称的高强度间歇训练 (HIIT)能一定程度减少在器材与环境方面的参与障碍并节省时间,但其"高强度"与"不充 分间歇"的组合使得大部分久坐及代谢疾病人群难以坚持下去 [5] 。因此,如何在生活中以便 捷高效的方式获得与传统运动相似或更优的健康促进效果遂成为新的运动诉求。 碎片化运动(exercise snacks,ES,直译为运动零食)提供了一种新的思路。最新大规 模队列研究发现,每天碎片化的累积 3 次 1 min 剧烈强度活动,与显著降低 27%的全因死 亡风险 [6] 与 49%的心血管疾病风险相关 [7] 。其次,近 3 年的随机对照干预试验显示,每天 3 次孤立(次间隔≥1 h)的 20 s 骑行冲刺 [8][9] 或爬楼 [10] ,即可显著改善峰值摄氧量且比 HIIT 有 着更高的时间经济性,将 ES 应用于久坐间断也可抵消久坐对心血管代谢的负面影响 [11][12][13][14] ES 源自"累积运动",旨在将单次持续运动拆分为多次并孤立地分布于全天 [15] 。2007 年 之前的研究大多将 ES 设计为单次 10 min、全天累积的中强度运动 [16][17][18] 。随后,研究逐渐 缩短单次运动时长,并提升单次运动强度。Francois 等人于 2014 年首次在学术期刊中使用 "exercise snacks",用于描述在三餐前进行的低量 HIIT [19] 。这一系列研究发现,ES 与等量 持续运动有类似甚至更优的健康效益,且在日常生活中便于实施。鉴于此,世界卫生组织 也将"运动时间持续 10 min"的专家共识更新为"任何持续时间运动的健康效益都可被累积" [ Rafiei [11] , et al.2021 ...
... Wolfe [13] , et al.2020 ...
Full-text available
碎片化运动(Exercise Snacks,ES)是以久坐间断和健康促进为目的,一天中多次孤立进行,强度中高至全力、单次持续时间≤1min或几个1min、次间间隔1-6h,对器材和环境要求低的一种运动策略。得益于ES“碎片化”和“生活化”的特征,其相较于传统运动具有更高的时间经济性、安排灵活性、运动愉悦感以及参与动机,并且安全。周期性应用ES可改善心肺适能、肌肉适能和体成分。作为久坐间断的干预措施,ES能抵消久坐对心血管代谢的不良影响并改善糖、脂代谢与血管功能。ES改善心肺适能可用中枢血流动力学适应与外周骨骼肌摄取及氧化重构进行解释,ES间断久坐改善糖、脂代谢与血管功能则与调节蛋白质转运、激素分泌与炎症等相关。兼具应用可行性和健康促进效果的双重优势使ES成为健康促进的新策略。未来研究应结合现代科技(如可穿戴设备),在办公室等真实环境中进行广泛调查与干预,并拓展更多类型人群与结局指标、探索其剂量效应及不同运动变量的影响及其作用机制。 Exercise snacks (ES) is an exercise strategy aimed at sedentary breaks and health promotion are performed in isolated bouts of moderate to all-out intensity exercises lasting ≤1 minute or several 1-minute sessions and performed periodically throughout the day with 1-6 hour intervals between sessions, and with low equipment and environmental requirements. The “snack” and “lifestyle” features of ES give it advantages in terms of time economy, flexibility of schedule, enjoyment of exercise, motivation to participate, and high adherence to exercise during the intervention, and it has also been shown to be safe. Long-term, regular ES improves cardiorespiratory fitness, muscle function, and body composition. As an intervention for sedentary breaks, ES counteracts the adverse effects of sedentary activity on cardiovascular metabolism and improves glucolipid metabolism and vascular function. ES improves cardiopulmonary fitness, as explained by central hemodynamic adaptation, peripheral skeletal muscle uptake, and oxidative remodeling. ES interruption of sedentary activity improves glucolipid metabolism and vascular function and is associated with the regulation of protein transport, hormone secretion, and inflammation. The combination of feasibility and health benefits makes ES a new strategy for health promotion. Future research should integrate modern technology to conduct a wide range of investigations and interventions in real-life situations such as schools, offices, and homes and to cover more types of people, explore dose effects and the impact of different exercise variables, expand outcome indicators, and explore the behavioral basis and physiological mechanisms.
... Exercise performed on the day preceding a high-fat meal Since 2014, 36 studies have confirmed that exercise performed on the evening prior to a morning high-fat meal (that is, a meal containing above 0.7 g of fat per kg body mass) lowers PPL, compared to no exercise. This has been shown in young, middle-aged and/or older men [14, 21-23, 27-43, 76, 77], young men and women [44], young or middle-aged women [45,67], normal and overweight individuals [68], overweight and obese individuals [24, 46,47] and adolescent boys and girls [48][49][50][51][52][53]. ...
... Most of the evidence until 2013 [9] and afterwards [30,56] shows that exercise accumulated in this way is as effective as continuous exercise in reducing PPL on the next day. This has also been found with cycling sprints spread over the day [44]. When short bouts of exercise are performed on the day of the meal(s), most studies find no effect on PPL [104][105][106][107][108][109][110], whereas some find a lowering effect [26, 63,64]. ...
We review recent findings on the ability of exercise to lower postprandial lipemia (PPL). Specifically, we answer why exercise is important in lowering PPL, when it is most effective to exercise to achieve this, what the preferred exercise is and how exercise reduces PPL. Most findings confirm the power of exercise to lower PPL, which is an independent risk factor for cardiovascular disease. Exercise is most effective when performed on the day preceding a high- or moderate-fat meal. This effect lasts up to approximately two days; therefore, one should exercise frequently to maintain this benefit. However, the time of exercise relative to a meal is not that important in real-life conditions, since one consumes several meals during the day; thus, an exercise bout will inevitably exert its lowering effect on PPL in one or more of the subsequent meals. Although moderate-intensity continuous exercise, high-intensity intermittent exercise (HIIE), resistance exercise and accumulation of short bouts of exercise throughout the day are all effective in lowering PPL, submaximal, high-volume interval exercise seems to be superior, provided it is tolerable. Finally, exercise reduces PPL by both lowering the rate of appearance and increasing the clearance of triacylglycerol-rich lipoproteins from the circulation.
... Conversely, interrupting prolonged sitting by standing has been shown to reduce these risks (10)(11)(12)(13)(14). Note that even short sprints of exercise have been shown to be of great health value (15,16). Consequently, how to encourage people to stand is a crucial behavioral question. ...
Full-text available
Nudges are interventions promoting healthy behavior without forbidding options or substantial incentives; the Apple Watch, for example, encourages users to stand by delivering a notification if they have been sitting for the first 50 minutes of an hour. On the basis of 76 billion minutes of observational standing data from 160,000 subjects in the public Apple Heart and Movement Study, we estimate the causal effect of this notification using a regression discontinuity design for time series data with time-varying treatment. We show that the nudge increases the probability of standing by up to 43.9% and remains effective with time. The nudge’s effectiveness increases with age and is independent of gender. Closing Apple Watch Activity Rings, a visualization of participants’ daily progress in Move, Exercise, and Stand, further increases the nudge’s impact. This work demonstrates the effectiveness of behavioral health interventions and introduces tools for investigating their causal effect from large-scale observations.
... This may be an explanation that why the fat oxidation cannot be further increased after consuming a high fat meal. Nonetheless, this present study indicated that time-restricted feeding increased the fasting and postprandial fat oxidation, which likely lead to improved fat metabolism or cardiometabolic health 28 . Moreover, the further research is required to investigate the effect of TRF on postprandial response after a high fat meal in the overweight or at-risk populations. ...
Full-text available
Studies have revealed that time-restricted feeding affects the fat oxidation rate; however, its effects on the fat oxidation rate and hyperlipidemia following high-fat meals are unclear. This study investigated the effects of 5-day time-restricted feeding on the fat oxidation rate and postprandial lipemia following high fat meals. In this random crossover experimental study, eight healthy male adults were included each in the 5-day time-restricted feeding trial and the control trial. The meals of the time-restricted feeding trial were provided at 12:00, 16:00, and 20:00. The meals of the control trial were provided at 08:00, 14:00, and 20:00. The contents of the meals of both trials were the same, and the calories of the meals met the 24-h energy requirement of the participants. After 5 days of the intervention, the participants consumed high-fat meals on the sixth day, and their physiological changes were determined. The fasting fat oxidation rate ( p < 0.001) and postprandial fat oxidation rate ( p = 0.019) of the time-restricted feeding trial were significantly higher than those of the control trial. The 24-h energy consumption and postprandial triglyceride, blood glucose, insulin, glycerol, and free fatty acid concentrations of the two trials showed no significant differences ( p > 0.05). The results revealed that 5 days of time-restricted feeding effectively increased the fasting and postprandial fat oxidation rate, but it did not affect postprandial lipemia.
Background E-sports require athletes to have high-speed reflexes and excellent memory skills. Whereas a single session of aerobic exercise has been shown to improve cognitive function, this paper aims is to investigate the effects of acute moderate-intensity aerobic exercise on the cognitive function of e-sports players and its time-course characteristics. Methods Thirty-four E-athletes were divided into 2 groups according to a random number table method, and 2 trials in a quiet physical fitness gym. The duration of each trial was approximately 1 hour. In the first trial: exercise group (64–76% of maximum heart rate for 30 minutes power cycling) and control group, cognitive function was tested, and results were automatically recorded before, immediately after, and 30 minutes after exercise using the human benchmark website ( The second trial crossed and swapped the interventions of the 2 groups, and the other test protocols were the same as the first. Results In both trials, the exercise intervention group showed significant improvements in speed accuracy ( P < .001, Cohen’s d = 1.406, 95% CI: 0.717–2.072; P = .005, Cohen’s d = 0.782, 95% CI: 0.227–1.319), visual memory ( P < .001, Cohen’s d = 1.416, 95% CI: 0.725–2.086; P = .015, Cohen’s d = 0.662, 95% CI: 0.127–1.181), and reaction time ( P < .001, Cohen’s d = 1.265, 95% CI: 0.610–1.898; P <.001, Cohen’s d = 0.979, 95% CI: 0.386–1.551) immediately after exercise compared to baseline. The exercise intervention group also showed significant improvement in speed accuracy 30 minutes after exercise compared to baseline ( P = .002 Cohen’s d = 0.869, 95% CI: 0.298–1.421; P = .009, Cohen’s d = 0.722, 95% CI: 0.177–1.249). In the first trial, the exercise intervention group showed significant improvements in visual memory and reaction time immediately after exercise compared to the control group ( P = .013, Cohen’s d = 0.904, 95% CI: 0.190–1.605; P = .027, Cohen’s d = 0.796, 95% CI: 0.090–1.490). The exercise intervention group also showed significant improvement in reaction time 30 minutes after exercise compared to baseline ( P = .009, Cohen’s d = 0.719, 95% CI: 0.174–1.246). There was no effect of exercise on sequence memory or the chimp test in both trials ( P > .05). Sequence effect analysis showed no influence on the order of the exercise intervention in both trials ( P = .912; P = .111; P = .226). Conclusion Acute moderate-intensity aerobic exercise significantly enhanced the speed accuracy, visual reaction time, and instantaneous memory of eSports players, and the effect could be extended up to 30 minutes after exercise.
Full-text available
Type 2 diabetes mellitus (T2DM) and sarcopenia (low skeletal muscle mass and function) share a bidirectional relationship. The prevalence of these diseases increases with age and they share common risk factors. Skeletal muscle fat infiltration, commonly referred to as myosteatosis, may be a major contributor to both T2DM and sarcopenia in older adults via independent effects on insulin resistance and muscle health. Many strategies to manage T2DM result in energy restriction and subsequent weight loss, and this can lead to significant declines in muscle mass in the absence of resistance exercise, which is also a first-line treatment for sarcopenia. In this review, we highlight recent evidence on established treatments and emerging therapies targeting weight loss and muscle mass and function improvements in older adults with, or at risk of, T2DM and/or sarcopenia. This includes dietary, physical activity and exercise interventions, new generation incretin-based agonists and myostatin-based antagonists, and endoscopic bariatric therapies. We also highlight how digital health technologies and health literacy interventions can increase uptake of, and adherence to, established and emerging treatments and therapies in older adults with T2DM and/or sarcopenia.
Purpose: To examine the effects of daily step-count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Methods: Ten healthy participants (5 females, 30±7 y) completed four different daily step-counts - 2,000 (2K), 5,000 (5K), 10,000 (10K), and 15,000 (15K) steps - on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking-bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FATOX) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-minutes following consumption of a HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), non-esterified fatty acids (NEFAs), insulin, and glucose. Results: Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2K versus 10K (+23±8 mg/dL, p=0.027), and NEFAs were significantly higher after 15K versus 2K (+86±23 µmol/L; p=0.006). No differences were found for insulin, glucose, or REE among conditions (all p>0.124). Similarly, RER (p=0.055; ηp2=0.24) and FATOX (p=0.070; ηp2=0.23) were not significantly different among conditions. Conclusion: In young adults, 10K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity.
Cardiovascular disease (CVD) is the leading non-communicable disease and cause of premature mortality globally. Despite well-established evidence of a cause-effect relationship between modifiable lifestyle behaviours and the onset of risk of chronic disease, preventative approaches to curtail increasing prevalence have been ineffective. This has undoubtedly been exacerbated by the coronavirus disease 2019 (COVID-19) pandemic, which saw widespread national lockdowns implemented to reduce transmission and alleviate pressure on strained healthcare systems. An unintended consequence of these approaches was a well-documented negative impact on population health in the context of both physical and mental well-being. Whilst the true extent of the impact of the COVID-19 pandemic on global health has yet to be fully realised or understood, it seems prudent to review effective preventative and management strategies that have yielded positive outcomes across the spectrum (i.e., individual to society). There is also a clear need to heed lessons learnt from the COVID-19 pandemic in the power of collaboration and how this can be used in the design, development, and implementation of future approaches to address the longstanding burden of CVD.
Exercise is a first-line therapy recommended for patients with type 2 diabetes (T2D). Although moderate to vigorous exercise (e.g. 150 min/wk) is often advised alongside diet and/or behavior modification, exercise is an independent treatment that can prevent, delay or reverse T2D. Habitual exercise, consisting of aerobic, resistance or their combination, fosters improved short- and long-term glycemic control. Recent work also shows high-intensity interval training is successful at lowering blood glucose, as is breaking up sedentary behavior with short-bouts of light to vigorous movement (e.g. up to 3min). Interestingly, performing afternoon compared with morning as well as post-meal versus pre-meal exercise may yield slightly better glycemic benefit. Despite these efficacious benefits of exercise for T2D care, optimal exercise recommendations remain unclear when considering, dietary, medication, and/or other behaviors.
The purpose of this systematic review was to synthesize the results from current literature examining the effects of prior exercise on the postprandial triglyceride (TG) response to evaluate current literature and provide future direction. A quantitative review was performed using meta-analytic methods to quantify individual effect sizes. A moderator analysis was performed to investigate potential variables that could influence the effect of prior exercise on postprandial TG response. Two hundred and seventy-nine effects were retrieved from 165 studies for the total TG response and 142 effects from 87 studies for the incremental area under the curve TG response. There was a moderate effect of exercise on the total TG response (Cohen’s d = −0.47; p < .0001). Moderator analysis revealed exercise energy expenditure significantly moderated the effect of prior exercise on the total TG response ( p < .0001). Exercise modality (e.g., cardiovascular, resistance, combination of both cardiovascular and resistance, or standing), cardiovascular exercise type (e.g., continuous, interval, concurrent, or combined), and timing of exercise prior to meal administration significantly affected the total TG response ( p < .001). Additionally, exercise had a moderate effect on the incremental area under the curve TG response (Cohen’s d = −0.40; p < .0001). The current analysis reveals a more homogeneous data set than previously reported. The attenuation of postprandial TG appears largely dependent on exercise energy expenditure (∼2 MJ) and the timing of exercise. The effect of prior exercise on the postprandial TG response appears to be transient; therefore, exercise should be frequent to elicit an adaptation.
Full-text available
The interaction of prolonged sitting with physical exercise for maintaining health is unclear. We tested the hypothesis that prolonged siting would have a deleterious effect on postprandial plasma lipemia (PPL, postprandial plasma triglycerides) and abolish the ability of an acute exercise bout to attenuate PPL. Seven healthy young men performed three interventions over 5 days (D1-5) in a randomized crossover design with > 1 week between interventions: 1) sitting >14h/d with hypercaloric energy balance (SH), 2) sitting >14h/d with net energy balance (SB), and 3) active walking/standing with net energy balance (WB) and sitting 8.4 h/d. The first high fat tolerance test (HFTT1) was performed on D3 following 2 days of respective interventions. On the evening of D4 subjects ran on a treadmill for 1-h at ~ 67% VO2max, followed by the second HFTT (HFTT2) on D5. Two days of prolonged sitting increased TG AUCI (i.e., incremental area under the curve for TG), irrespective of energy balance, compared to WB (27% in SH, p=0.003 and 26% in SB, p=0.046). Surprisingly, after four days of prolonged sitting (i.e.; SH and SB), the acute exercise on D4 failed to attenuate TG AUCI or increase relative fat oxidation in HFTT2, compared to HFTT1, independent of energy balance. In conclusion, prolonged sitting over several days was sufficient to amplify PPL and to abolish the beneficial effect of acute exercise on lowering PPL and raising fat oxidation, regardless of energy balance. This underscores the importance of limiting sitting time even in people who have exercised.
Full-text available
Sedentary behavior is highly prevalent in office-based workplaces; however, few studies have assessed the attributes associated with this health risk factor in the workplace setting. This study aimed to identify the correlates of office workers' objectively-assessed total and prolonged (≥ 30 min bouts) workplace sitting time. Participants were 231 Australian office workers recruited from 14 sites of a single government employer in 2012–13. Potential socio-demographic, work-related, health-related and cognitive-social correlates were measured through a self-administered survey and anthropometric measurements. Associations with total and prolonged workplace sitting time (measured with the activPAL3) were tested using linear mixed models. Worksites varied significantly in total workplace sitting time (overall mean [SD]: 79% [10%] of work hours) and prolonged workplace sitting time (42% [19%]), after adjusting for socio-demographic and work-related characteristics. Organisational tenure of 3–5 years (compared to tenure > 5 years) was associated with more time spent in total and prolonged workplace sitting time, while having a BMI categorised as obese (compared to a healthy BMI) was associated with less time spent in total and prolonged workplace sitting time. Significant variations in sitting time were observed across different worksites of the same employer and the variation remained after adjusting for individual-level factors. Only BMI and organisational tenure were identified as correlates of total and prolonged workplace sitting time. Additional studies are needed to confirm the present findings across diverse organisations and occupations.
Full-text available
Objective: To encourage increased participation in physical activity among Americans of all ages by issuing a public health recommendation on the types and amounts of physical activity needed for health promotion and disease prevention. Participants: A planning committee of five scientists was established by the Centers for Disease Control and Prevention and the American College of Sports Medicine to organize a workshop. This committee selected 15 other workshop discussants on the basis of their research expertise in issues related to the health implications of physical activity. Several relevant professional or scientific organizations and federal agencies also were represented. Evidence: The panel of experts reviewed the pertinent physiological, epidemiologic, and clinical evidence, including primary research articles and recent review articles. Consensus process: Major issues related to physical activity and health were outlined, and selected members of the expert panel drafted sections of the paper from this outline. A draft manuscript was prepared by the planning committee and circulated to the full panel in advance of the 2-day workshop. During the workshop, each section of the manuscript was reviewed by the expert panel. Primary attention was given to achieving group consensus concerning the recommended types and amounts of physical activity. A concise "public health message" was developed to express the recommendations of the panel. During the ensuing months, the consensus statement was further reviewed and revised and was formally endorsed by both the Centers for Disease Control and Prevention and the American College of Sports Medicine. Conclusion: Every US adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably all, days of the week.
Full-text available
Aim: To compare the cumulative (three-day) effect of prolonged sitting on metabolic responses during a mixed meal tolerance test (MTT), with sitting that is regularly interrupted with brief bouts of light-intensity walking. Research design and methods: Overweight/obese adults (n=19) were recruited for a randomized, three-day, outpatient, crossover trial involving: 1) 7-hour days of uninterrupted sitting (SIT); and, 2) 7-hour days of sitting with light-intensity activity breaks [BREAKS; 2-minutes of treadmill walking (3.2 km/hour) every 20 minutes (total: 17 breaks/day)]. On days 1 and 3, participants underwent a MTT (75g carbohydrate, 50g fat), and the incremental area under the curve (iAUC) was calculated from hourly blood samples. GEE models were adjusted for gender, BMI, energy intake, treatment order and pre-prandial values to determine effects of time, condition and time x condition. Results: The glucose iAUC was 1.3 ± 0.5 and 1.5 ± 0.5 (mean difference ± SEM) higher in SIT compared with BREAKS on days 1 and 3 respectively (condition effect: P=0.001), with no effect of time (P=0.48) or time x condition (P=0.8). The insulin iAUC was also higher on both days in SIT (Day 1: ∆151 ± 73, Day 3: ∆91 ± 73, P=0.01), with no effect of time (P=0.52) or time x condition (P=0.71). There was no between-treatment difference in triglycerides iAUC. Conclusion: There were significant between-condition effects but no temporal change in metabolic responses to MTT, indicating that breaking up sitting over three days sustains, but does not enhance, the lowering of postprandial glucose and insulin.
Acute exercise improves postprandial lipemia, glucose tolerance, and insulin sensitivity, all of which are risk factors for cardiovascular disease. However, recent research suggests that prolonged sedentary behavior might abolish these healthy metabolic benefits. Accordingly, this study aimed to elucidate the impact of an acute bout of exercise on postprandial plasma triglyceride, glucose, and insulin concentrations after 4 days of prolonged sitting (~13.5 h/day). Ten untrained to recreationally active men ( n = 5) and women ( n = 5) completed a counterbalanced, crossover study. Four days of prolonged sitting without exercise (SIT) were compared with 4 days of prolonged sitting with a 1-h bout of treadmill exercise (SIT + EX; 63.1 ± 5.2% V̇o 2max ) on the evening of the fourth day. The following morning, participants completed a high-fat/glucose tolerance test (HFGTT), during which plasma was collected over a 6-h period and analyzed for triglycerides, glucose, and insulin. No differences between trials ( P > 0.05) were found in the overall plasma triglyceride, glucose, or insulin responses during the HFGTT. This lack of difference between trials comes with similarly low physical activity (~3,500–4,000 steps/day) on each day except for the 1-h bout of exercise during SIT + EX the day before the HFGTT. These data indicate that physical inactivity (e.g., sitting ~13.5 h/day and <4,000 steps/day) creates a condition whereby people become “resistant” to the metabolic improvements that are typically derived from an acute bout of aerobic exercise (i.e., exercise resistance). NEW & NOTEWORTHY In people who are physically inactive and sitting for a majority of the day, a 1-h bout of vigorous exercise failed to improve lipid, glucose, and insulin metabolism measured the next day. It seems that something inherent to inactivity and/or prolonged sitting makes the body resistant to the 1 h of exercise preventing the normally derived metabolic improvements following exercise.
Importance Approximately 80% of US adults and adolescents are insufficiently active. Physical activity fosters normal growth and development and can make people feel, function, and sleep better and reduce risk of many chronic diseases. Objective To summarize key guidelines in the Physical Activity Guidelines for Americans, 2nd edition (PAG). Process and Evidence Synthesis The 2018 Physical Activity Guidelines Advisory Committee conducted a systematic review of the science supporting physical activity and health. The committee addressed 38 questions and 104 subquestions and graded the evidence based on consistency and quality of the research. Evidence graded as strong or moderate was the basis of the key guidelines. The Department of Health and Human Services (HHS) based the PAG on the 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Recommendations The PAG provides information and guidance on the types and amounts of physical activity to improve a variety of health outcomes for multiple population groups. Preschool-aged children (3 through 5 years) should be physically active throughout the day to enhance growth and development. Children and adolescents aged 6 through 17 years should do 60 minutes or more of moderate-to-vigorous physical activity daily. Adults should do at least 150 minutes to 300 minutes a week of moderate-intensity, or 75 minutes to 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. They should also do muscle-strengthening activities on 2 or more days a week. Older adults should do multicomponent physical activity that includes balance training as well as aerobic and muscle-strengthening activities. Pregnant and postpartum women should do at least 150 minutes of moderate-intensity aerobic activity a week. Adults with chronic conditions or disabilities, who are able, should follow the key guidelines for adults and do both aerobic and muscle-strengthening activities. Recommendations emphasize that moving more and sitting less will benefit nearly everyone. Individuals performing the least physical activity benefit most by even modest increases in moderate-to-vigorous physical activity. Additional benefits occur with more physical activity. Both aerobic and muscle-strengthening physical activity are beneficial. Conclusions and Relevance The Physical Activity Guidelines for Americans, 2nd edition, provides information and guidance on the types and amounts of physical activity that provide substantial health benefits. Health professionals and policy makers should facilitate awareness of the guidelines and promote the health benefits of physical activity and support efforts to implement programs, practices, and policies to facilitate increased physical activity and to improve the health of the US population.
Background Compared to prolonged sitting, regular activity breaks immediately lower postprandial glucose and insulin, but not triglyceride responses. Postprandial triglycerides can be lowered by physical activity but the effect is often delayed by ∼12-24 h Objective To determine whether regular activity breaks affect postprandial triglyceride response in a delayed manner similar to physical activity. Methods In a randomized crossover trial, 36 adults (BMI 23.9 kg·m² (SD 3.9)) completed four two-day interventions: 1. Prolonged Sitting (SIT); 2. Prolonged Sitting with 30 min of continuous walking (60% VO2max), at the end of Day 1 (SIT+PAD1); 3. Sitting with 2 min of walking (60% VO2max) every 30 min (RAB); 4. A combination of the continuous walking and regular activity breaks in 2 and 3 above (RAB+PAD1). Postprandial plasma triglyceride, non-esterified fatty acids (NEFA), glucose, and insulin responses were measured in venous blood over 5 h on Day 2. Results Compared to SIT, both RAB (difference: -43.61 mg·dL⁻¹·5h; 95% CI –83.66 to -2.67; p=0.035) and RAB+PAD1 (-65.86 mg·dL⁻¹·5h; 95% CI -112.14 to -19.58; p=0.005) attenuated triglyceride tAUC. RAB+PAD1 produced the greatest reductions in insulin tAUC (-23%; 95% CI -12 to -31%; p<0.001) while RAB resulted in the largest increase in NEFA (tAUC, 10.08 mg·dL⁻¹·5h; 95% CI 5.60 to 14.84; p<0.001). There was no effect on glucose tAUC (p=0.290). Conclusions Postprandial triglyceride response is attenuated by regular activity breaks, when measured ∼24 h after breaks begin. Combining regular activity breaks with 30 min of continuous walking further improves insulinaemic and lipidaemic responses.
Background: High amounts of sedentary behaviour have been associated with increased risks of several chronic conditions and mortality. However, it is unclear whether physical activity attenuates or even eliminates the detrimental effects of prolonged sitting. We examined the associations of sedentary behaviour and physical activity with all-cause mortality. Methods: We did a systematic review, searching six databases (PubMed, PsycINFO, Embase, Web of Science, Sport Discus, and Scopus) from database inception until October, 2015, for prospective cohort studies that had individual level exposure and outcome data, provided data on both daily sitting or TV-viewing time and physical activity, and reported effect estimates for all-cause mortality, cardiovascular disease mortality, or breast, colon, and colorectal cancer mortality. We included data from 16 studies, of which 14 were identified through a systematic review and two were additional unpublished studies where pertinent data were available. All study data were analysed according to a harmonised protocol, which categorised reported daily sitting time and TV-viewing time into four standardised groups each, and physical activity into quartiles (in metabolic equivalent of task [MET]-hours per week). We then combined data across all studies to analyse the association of daily sitting time and physical activity with all-cause mortality, and estimated summary hazard ratios using Cox regression. We repeated these analyses using TV-viewing time instead of daily sitting time. Findings: Of the 16 studies included in the meta-analysis, 13 studies provided data on sitting time and all-cause mortality. These studies included 1 005 791 individuals who were followed up for 2-18·1 years, during which 84 609 (8·4%) died. Compared with the referent group (ie, those sitting <4 h/day and in the most active quartile [>35·5 MET-h per week]), mortality rates during follow-up were 12-59% higher in the two lowest quartiles of physical activity (from HR=1·12, 95% CI 1·08-1·16, for the second lowest quartile of physical activity [<16 MET-h per week] and sitting <4 h/day; to HR=1·59, 1·52-1·66, for the lowest quartile of physical activity [<2·5 MET-h per week] and sitting >8 h/day). Daily sitting time was not associated with increased all-cause mortality in those in the most active quartile of physical activity. Compared with the referent (<4 h of sitting per day and highest quartile of physical activity [>35·5 MET-h per week]), there was no increased risk of mortality during follow-up in those who sat for more than 8 h/day but who also reported >35·5 MET-h per week of activity (HR=1·04; 95% CI 0·99-1·10). By contrast, those who sat the least (<4 h/day) and were in the lowest activity quartile (<2·5 MET-h per week) had a significantly increased risk of dying during follow-up (HR=1·27, 95% CI 1·22-1·31). Six studies had data on TV-viewing time (N=465 450; 43 740 deaths). Watching TV for 3 h or more per day was associated with increased mortality regardless of physical activity, except in the most active quartile, where mortality was significantly increased only in people who watched TV for 5 h/day or more (HR=1·16, 1·05-1·28). Interpretation: High levels of moderate intensity physical activity (ie, about 60-75 min per day) seem to eliminate the increased risk of death associated with high sitting time. However, this high activity level attenuates, but does not eliminate the increased risk associated with high TV-viewing time. These results provide further evidence on the benefits of physical activity, particularly in societies where increasing numbers of people have to sit for long hours for work and may also inform future public health recommendations. Funding: None.
-Nine male subjects performed two bouts of 30-s maximal isokinetic cycling. Each bout of exercise was performed at 80 revolutions/min and was separated by 4 min of recovery. Mixed-muscle phosphocreatine (: PCr resynthesis during recovery (88.1 ±6.1%) was positively correlated with the restoration of total work production during bout 2 (r = 0.80, P < 0.05). During bout 1, ATP and PCr utilization were greater in type II compared with type I fibers (P < 0.01 and P< 0.05, respectively). The subsequent 4-min period of recovery was insufficient to allow total restoration of ATP and PCr in type II fibers, but restoration of ATP and PCr in type I fibers was almost complete. During the second bout of exercise, ATP and PCr utilization were reduced in type II fibers (P < 0.01), without a corresponding change in type I fibers, and performance was also significantly reduced. The reduction in work capacity observed during bout 2 may have been related to a slower resynthesis, and consequently a reduced availability, of ATP and PCr in type II fibers.