Isabelle J Dionne

• Professor
• Université de Sherbrooke

Background Individuals affected by the post-covid condition (PCC) show an increased fatigue and the so-called post-exertion malaise (PEM) that led health professionals to advise against exercise although accumulating evidence indicates the contrary. The goal of this study is to determine the impact of a closely monitored 8-week mixed exercise progr...

Resistance training (RT) promotes skeletal muscle (Skm) hypertrophy, increases muscular strength, and improves metabolic health. Whether changes in fat-free mass (FFM; a surrogate marker of muscle hypertrophy) moderate RT-induced improvements in glucose homeostasis has not been determined, despite extensive research on the benefits of RT for health...

Mitochondrial dysfunctions are thought to contribute to muscle atrophy and weakness that develop during ageing and mechanical unloading caused by immobilization, bed rest and microgravity. Older adults are at greater risk of developing muscle and mitochondrial dysfunctions in response to unloading. Although exercise is well known to promote muscle...

Weightlessness during spaceflight can harm various bodily systems, including bone density, muscle mass, strength and cognitive functions. Exercise appears to somewhat counteract these effects. A terrestrial model for this is head‐down bedrest (HDBR), simulating gravity loss. This mirrors challenges faced by older adults in extended bedrest and spac...

Background: Individuals affected by the post-covid condition (PCC) show an increased fatigue and the so-called post-exertion malaise (PEM) that led health professionals to advise against exercise although accumulating evidence indicates the contrary. The goal of this study is to determine the impact of a closely monitored 8-week mixed exercise prog...

Background: Individuals affected by the post-covid condition (PCC) show an increased fatigue and the so-called post-exertion malaise (PEM) that led health professionals to advise against exercise although accumulating evidence indicates the contrary. The goal of this study is to determine the impact of a closely monitored 8-week mixed exercise prog...

Healthy aging and physical activity practice: The missing link Isabelle J. Dionne, PhD, Professor, Université de Sherbrooke, walks us through physical activity practice and how it impacts research on healthy aging. Major public health agencies around the world urge the older population to get on the move while cities and states invest more and more...

Background Following SARS-CoV-2 infection a significant proportion of convalescent individuals develop the post-COVID condition (PCC) that is characterized by wide spectrum of symptoms encompassing various organs. Even though the underlying pathophysiology of PCC is not known, detection of viral transcripts and antigens in tissues other than lungs...

Introduction: Head-down bed rest (HDBR) has long been used as an analog to microgravity and it also enables studying the changes occurring with aging. Exercise is the most effective countermeasure for the deleterious effects of inactivity. The aim of this study was to investigate the efficacy of an exercise countermeasure in healthy older particip...

Background Following SARS-CoV-2 infection a significant proportion of convalescent individuals develop the post-COVID condition (PCC) that is characterized by wide spectrum of symptoms encompassing various organs. Even though the underlying pathophysiology of PCC is not known, detection of viral transcripts and antigens in tissues other than lungs...

Background Homocysteine (Hcy) has been associated with several health problems, including reduced physical capacity. No study appears to have looked at the role of Hcy values longitudinally on physical capacity deterioration in older adults. The objective is to examine cross-sectional and prospective associations between Hcy values and frailty in t...

Aging and family history of type 2 diabetes (T2D) are known risk factors of T2D. Younger first-degree relatives (FDR) of T2D patients have shown early metabolic alterations, which could limit exercise’s ability to prevent T2D. Thus, the objective was to determine whether exercise metabolism was altered during submaximal exercise in FDR postmenopaus...

Long-duration spaceflights (LDS) will require astronauts to train autonomously in compact and very isolated environments. Blood flow restriction (BFR) training is safe and effective for eliciting gains in muscle mass and strength across multiple populations. The first parts of this study series aim to assess the effectiveness of low intensity resis...

In terms of exercise countermeasures, long-duration spaceflights (LDS) mark a turning point since current exercise devices can no longer be used due to their large size. Conventional guidelines often call for high-intensity resistance training (HIRT), which represents an important mechanical load and a risk of injury. BFR combined with low-intensit...

Background: The objective was to compare the effects of low-volume highintensity interval training (HIIT) to moderate-intensity continuous training (MICT) on the inflammatory profile in older women with type 2 diabetes (T2D). Methods: Thirty older physically inactive women (68 ± 5 years) with T2D were randomized in two groups: HIIT (75 min/week w...

Background It is well established that body composition influences metabolic health, but emerging data are conflicting with the largely purported idea that a large fat-free mass (FFM) has a protective effect on health. A potential explanation for these discrepancies is the way FFM is represented. The first objective is to determine the association...

Background and aims To compare the effect of a low-volume walking high-intensity interval training (HIIT) to moderate-intensity continuous training (MICT) on risk of cardiovascular diseases and physical capacity in older women with type 2 diabetes (T2D). Methods Thirty inactive older women with T2D were randomized into either HIIT (75 min/week) or...

Skeletal muscle (SM) tissue has been repetitively shown to play a major role in whole-body glucose homeostasis and overall metabolic health. Hence, SM hypertrophy through resistance training (RT) has been suggested to be favorable to glucose homeostasis in different populations, from young healthy to type 2 diabetic (T2D) individuals. While RT has...

Objectives: First, to establish the respective ability of body mass index (BMI), waist circumference (WC), and relative fat mass index (RFM), to estimate body fat (BF%) measured by DXA (DXA-BF%) and correctly identify postmenopausal women living with obesity (BF% > 35). Second, to identify the best indicator of successful weight-loss intervention...

Sarcopenic obesity is associated with several negative health outcomes. However, the prevalence of this condition – and the relationship to physical performance parameters – varies across definitions. The aim of this cross-sectional investigation was to describe the prevalence of sarcopenic obesity using different published definitions and their re...

Go beyond aging theories and examine the physiological and physical impacts of aging. Exercise and Physical Activity for Older Adults takes a close look at the physical implications of the aging process and how health, physical activity, and exercise interact in aging adults. With an international team of contributors composed of leading experts fr...

Menopause transition is associated with detrimental changes in physical activity, body composition, and metabolic profile. Although physical activity energy expenditure (PAEE) is inversely associated with metabolic syndrome (MetS) in individuals at higher risk of cardiovascular disease, the association is unknown in low-risk individuals. The aim of...

Fat‐free mass (FFM) has long been recognized to play a role in metabolic homeostasis. Over the years, it has become widely accepted by the scientific and general community alike that having a greater FFM can be protective for metabolic health. Hence, in the context of an aging population concurrently facing sarcopenia and an elevated incidence of m...

Intradialytic exercise is feasible and yields substantial clinical benefits in middle-aged patients. However, evidence is scarce in older hemodialysis patients. Objective: To assess the feasibility and clinical benefits of supervised, intradialytic exercise in older patients. Methods: Multicenter one-arm feasibility study. The main outcome was...

Exercise interventions are acknowledged non-pharmacological avenues for improving cardiovascular disease (CVD) outcomes in people living with type 2 diabetes (T2D). The intricate nature of exercise training (i.e. intensity, volume, frequency) provides training-specific cardiovascular benefits, but the underlying mechanisms remain misunderstood. Not...

Moderate-intensity continuous aerobic training (MICT; 150 min/week) is known for its acute glucose-lowering effect in type 2 diabetic (T2D) patients. In its most recent guidelines, Diabetes Canada also suggested high-intensity-interval training (HIIT). However, results from studies on the acute effect of HIIT on capillary blood glucose (capBG) leve...

Because muscle tissue, as main component of fat-free mass (FFM), accounts for the majority of glucose uptake under insulin-stimulated conditions, it is largely purported that a larger FFM is associated with a better glucose homeostasis (GH). Hence, increasing or maintaining FFM with exercise training is recommended to manage T2D. However, interindi...

Objective : The purpose of this cross-sectional study was to investigate the effect of PAEE levels on MetS severity in obese postmenopausal women displaying a low Framingham risk score (FRS).

Background Aging, cancer and its treatment all contribute to increase the risk of deconditioning and sedentary behaviors. Mixed exercise is recognized to counteract the effects of aging and deconditioning as well as improving physical capacity during cancer treatment in adults. Aims To determine the impact of a mixed exercise program (MXEP) to imp...

It has been shown that individuals with first-degree relatives (FDR) with type 2 diabetes (T2D) have an increased risk of developing T2D. While physical activity (PA) was demonstrated to lessen this risk, a positive 24h post-exercise energy balance could reduce or cancel the exercise-induced benefits on insulin sensitivity. Interestingly, FDRs were...

Background and Objectives: Fatigue is one of the characteristics defining frailty. However, the mechanisms leading to fatigue are still poorly understood. Our objectives were to assess the efficacy of energy utilization (EU) during walking in frail older persons and their level of fatigue. Research Design and Methods: Clinical study of a convenient...

We wish to thank Lee et al. for their response to our recent letter to the editor, as well as the editors for allowing us to reply. The opening statement in the response of Lee et al. read that in our letter we “suggested that a lower fat mass (FM) accompanied by a higher fat‐free mass (FFM) is the main driver of the protective effect on metabolic...

Background: It was reported that cow’s milk-based supplementation after resistance training reduced fat mass in older men. The reasons behind this beneficial impact remain to be elucidated. Hence, the aim of this study was to determine the effect of a cow’s milk-based supplementation after resistance exercise on lipid oxidation and systemic fat mob...

Background: Kinesiophobia, the fear that movement and physical activity could worsen side effects such as fatigue and pain, is a barrier to exercise in cancer patients. Physical inactivity and deconditioning can lead to functional decline, higher mortality risk and lower quality of life, in older adults, and even more in oncogeriatrics because of a...

The role of fat‐free mass (FFM) in maintaining metabolic homeostasis has gained interest in the past two decades. Although exact mechanisms have never been pinpointed, it is commonly accepted in the scientific and clinical communities that a greater FFM would play a protective role in glucose homeostasis and metabolic health. This article is protec...

INTRODUCTION: Type 2 diabetes (T2D) and aging are both important risk factors for cardiovascular diseases. Improving fat oxidation with exercise is essential to improve glycemic control and reduce the risk of T2D-related complications. Aerobic exercise can enhance fat oxidation when prescribed at the right intensity. In this context, moderate inten...

INTRODUCTION: The metabolic syndrome (MetS) is an accumulation of metabolic abnormalities which increases the risk of cardiovascular diseases and type 2 diabetes. Since fat-free mass (FFM) is a metabolically active tissue, it is generally recognized that a greater FFM has a protective effect on the risk of developing MetS. This assumption is often...

Background: Body mass index (BMI) is often criticised since it doesn’t consider sex, age and ethnicity, which may affect the height scaling exponent of the equation. Aims: First, to identify specific height scaling exponents (α) based on sex, age and ethnicity. Second, to assess the performance of the current vs the proposed BMI equations (1) to pr...

Background: The aim of this study was to identify modifiable risk factors associated with isolated impaired fasting glucose (IFG), isolate impaired glucose tolerance (IGT), or combined IFG-IGT in men and women aged 50 years and older. Methods: Cross-sectional analyses were performed in 703 men and women aged between 50 and 80 years old from NHAN...

Objectives: To compare the effect of low-volume HIIT to moderate-intensity aerobic training (MICT) on fat mass, cardiometabolic profile and physical capacity and confirm its feasibility in older women. Methods: Inactive older women (60-75 years) were randomly assigned to 8 weeks of either HIIT (75 min/week; n=9) or MICT (150 min/week; n=9). Body...

Background: A greater fat-free mass (FFM) is purported to be associated with protective effects on insulin resistance (IR). However, recent studies suggested negative associations between FFM and IR. Objectives: (1) To explore the direction of the association between FFM and IR in a large heterogeneous sample after controlling for confounding fa...

We aimed to longitudinally assess the relationship between changing brain energy metabolism (glucose and acetoacetate) and cognition during healthy aging. Participants aged 71 ± 5 year underwent cognitive evaluation and quantitative positron emission tomography (PET) and magnetic resonance imaging (MRI) scans at baseline (N = 25) and two (N = 25) a...

Obesity in older adults results from several interacting factors. Consequently, interventions have shown mitigated effects. We determined (a) the different subgroups of older adults with obesity based on clusters of associated comorbidities and (b) the trajectory of these clusters to assess their stability over 3 years and factors contributing to t...

We aimed to longitudinally assess the relationship between changing brain energy metabolism (glucose and acetoacetate) and cognition during healthy aging. Participants aged 71 ± 5 y underwent cognitive evaluation and quantitative positron emission tomography (PET) and magnetic resonance imaging (MRI) scans at baseline (N=25) and two (N=25) and four...

A low-glycemic index (LGI) diet combined with 150 minutes/week of moderate-intensity continuous aerobic training (MICT) is recommended to improve glucose control and cardiovascular risk factors. Because of its time-efficiency, low-volume high-intensity interval training (HIIT; 75 min/week) may be interesting in this context. Therefore, the goal of...

High-intensity interval training (HIIT) is proposed as a potent strategy to control hypertension in individuals at high risk of cardiovascular disease (CVD). However, its effect on CVD risk in older adults with type 2 diabetes (T2D) remains unclear. Our objective was to compare the effects of low-volume HIIT and current aerobic exercise recommendat...

Background: Obesity in older adults results from several interacting factors. Consequently, interventions have shown mitigated effects. Objectives: We determined 1) the different subgroups of obese elderly based on clusters of associated comorbidities and 2) the trajectory of these clusters to assess their stability over 3 years and factors contrib...

Background: Because of its satiating effect, it has been widely purported that a high-protein beverage may reduce subsequent appetite and food intake in healthy aged individuals, therefore annihilating any supplemental effect. Aims: The goal of the study was to examine the impact of a post-exercise protein supplement from dairy products in the h...

Aging is characterized by physiological and morphological changes that affect body composition, strength, and function, ultimately leading to sarcopenia. This condition results in physical disability, falls, fractures, poor quality of life, and increased health care costs. Evidence suggests that increased consumption of dietary protein and physical...

The objectives of this study were to determine (i) whether a 5-day aerobic exercise (AE) program combined with a medium-chain triglyceride (MCT) supplement would increase the plasma ketone response in older women more than either intervention alone and (ii) whether ketonemia after these combined or separate treatments was alike in normoglycemic (NG...

Objective: A sex-specific standard waist circumference (WC) is widely used to determine cardiometabolic risk across ages even though aging impacts the link between fat distribution and cardiometabolic risk. The objective was to propose WC thresholds that better predict metabolic abnormalities according to sex, age, and body mass index (BMI) catego...

Background We have previously reported on the benefits of Pre-Surgical Exercise Training (PreSET) on physical fitness and social interactions in subjects awaiting bariatric surgery (BS). However, data are needed to know whether these benefits are maintained post-BS. Objectives The purpose of this paper was to evaluate the effect of PreSET on physic...

Several studies suggest that low-volume high intensity interval training (HIIT; 75 min/week) is a time-efficient strategy, compared to moderate intensity continuous aerobic training (MICT; 150 min/week), to control type 2 diabetes (T2D). However, its feasibility and impact when combined with a low-glycemic index (LGI) diet, as recommended for T2D p...

Low-volume high-intensity interval training (HIIT; 75 min/week) has gained in popularity and is promoted as a time-efficient strategy to reduce fat mass, improve metabolic profile and physical capacity compared to moderate-intensity continuous aerobic training (MICT; 150 min/week). Given that the prevalence of abdominal obesity is higher in elder w...

Introduction : Aging is associated with a higher risk of metabolic diseases and functional incapacities as well as an increase in sedentary behaviour time (SBT) and a loss of strength (dynapenia). Cancer treatment exacerbates these conditions and physical activity has been shown to be an efficient strategy to counteract these problems. We seek to d...

We aimed to identify predictors of insulin resistance in community-dwelling participants of the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). A total of 288 subjects (75.3 ± 4 years) with complete datasets were identified as insulin-resistant (n=96) and insulin-sensitive (n=192) over a 3-year period by trajectory analyses of...

We determined insulin resistant subjects over a 3-year period by trajectory analyses of the HOMA-IR in a sample of non-diabetic, participants of the NuAge Study. Muscle mass index and % body fat were derived from DXA and bioimpedance. Physical activity was assessed. Protein intakes were calculated. Serum biomarker profile included adiponectin, lept...

The impact of high-intensity interval training (HIIT) compared to the current exercise recommendations (moderate intensity continuous aerobic exercise; CONT) has to be verified in obese older women before being used by health professionals. Objective: The purpose of this study is to compare the effect of HIIT to CONT on body composition, metabolic...

Excess weight and menopause are two major factors increasing aging women’s vulnerability to chronic diseases. However, social position and socioeconomic status have also been identified as major determinants influencing both health behaviors and the development of such diseases. This study focuses on the socioeconomic variations of behavioral risk...

Socioeconomic inequalities in health persist despite major investments in illness prevention campaigns and universal healthcare systems. In this context, the increased risks of chronic diseases of specific sub-groups of vulnerable populations should be further investigated. The objective of this qualitative study is to examine the interaction betwe...

Objective: To verify the efficacy of phytoestrogen supplementation combined with aerobic and resistance training on the improvement of climacteric symptoms and health-related quality of life (HRQoL) in postmenopausal women. Methods: From a pool of women who had participated in a 1-year intervention study and were randomly assigned to either exerci...

Background: Aerobic training has some benefits for delaying the onset or progression of Alzheimer’s disease (AD). Little is known about the implication of the brain’s two main fuels, glucose and ketones (acetoacetate), associated with thesebenefits. Objective: To determine whether aerobic exercise training modifies brain energy metabolism in mild A...

Background: Experts recommend physical activity (PA) to optimize bariatric surgery (BS) results. However, evidence on the effect of PA before BS is missing. The aim of this study was to assess the impact of adding a Pre-Surgical Exercise Training (PreSET) to an interdisciplinary lifestyle intervention on physical fitness, quality of life, PA barri...

Background/Study context: Determining whether C-reactive protein (CRP), blood lipids, total and trunk fat mass (FM), and waist circumference (WC) are associated with changes in physical capacity over 3 years (Δ) in elderly. Methods: One hundred twenty-two men and women 68–83 years of age participated in a 3-year follow-up study. Physical capacity w...

This study aims to (1) describe participation in four physical activity (PA) domains across life and (2) examine the influence of PA during adolescence, early, middle, and later adulthood on health variables at older age. This observational study was conducted in 1378 generally healthy older adults (age 67-84 at baseline in 2003-2005; 52% women) in...

Objective: The aim of this study was to examine if overweight postmenopausal women who do not experience fat mass loss after a 1-year aerobic exercise (AE) and resistance training (RT) program can still improve physical fitness. Methods: Thirty-one overweight women (body mass index 28-40 kg/m or waist circumference ≥88 cm) participated in three...

Adequate protein intake and resistance training are effective strategies to maintain muscle mass, but the effect of their combination on metabolic profile during weight loss remains to be determined in older adults. The main objective of this study was to determine the effect of a 16-week high-protein caloric restriction combined with resistance tr...

Introduction: Conflicting results have been reported concerning the prevalence of cardiometabolic risk factors in women experiencing vasomotor symptoms (VMS). Objectives: To compare cardiometabolic risk factors between women with and without VMS during the menopause transition and to determine the influence of physical activity on the prevalence...

Fat free mass (FFM), which is majorly composed of skeletal muscle tissues, is generally associated with health and well-being. For the past decades, scientific literature has proposed higher FFM to be beneficial for the metabolic profile and, more particularly, for glucose homeostasis. Recent results from our study group led us to re-examine the as...

The loss of muscle mass (sarcopenia) with aging is related with a progressive loss of muscle strength and physical capacity. Resistance exercise and milk-based protein supplementation have been demonstrated as significant countermeasures to sarcopenia and the loss of muscle strength. However, using high doses of proteins can act as a meal replaceme...

Objective The common belief that high muscle mass improves insulin sensitivity is controversial and even recent studies have established that larger muscle mass is associated with insulin resistance in sedentary postmenopausal women. Physical activity induces a beneficial effect in muscle size and its metabolic properties. Hence, larger muscle mass...

Chronic effects of two different exercise environments on self-chosen intensity and physiological adaptations were examined in postmenopausal women. Twenty-three healthy to overweight (body mass index (BMI) 22 to 29 kg/m2) postmenopausal women were assigned to either: 1) Indoor training, 2) Outdoor training, and performed three weekly training sess...

Our primary objective in this study was to quantify whole brain and regional cerebral metabolic rates of glucose (CMRg) in young and older adults in order to determine age-normalized reference CMRg values for healthy older adults with normal cognition for age. Our secondary objectives were to-(i) report a broader range of metabolic and endocrine pa...

The decrease in resting energy expenditure (REE) and fat oxidation with aging is associated with an increase in fat mass and both could be prevented by exercise such as resistance training. Dairy consumption have also been shown to promote fat mass loss in different subpopulations and to be positively associated with fat oxidation. Therefore, we so...

Sarcopenia has been associated with increased systemic inflammation and risk of physical disability in older adults. Recently, extracellular heat shock protein 72 (eHSP72) was proposed as a biomarker of sarcopenia but its response to interventions designed to increase muscle mass has never been evaluated. The present study was designed to (1) asses...

Objectives: Contribute evidence towards the complex interrelationships of body composition, insulin sensitivity and protein intake independently from adiposity in an older population. Design: This is a cross-sectional analysis of an existing dataset in which a literature-supported model linking together the variables of interest is tested using...

Background In class II and III obese individuals, lifestyle intervention is the first step to achieve weight loss and treat obesity-related comorbidities before considering bariatric surgery. A systematic review, meta-analysis, and meta-regression were performed to assess the impact of lifestyle interventions incorporating a physical activity (PA)...

Background: We showed that obese insulin resistant postmenopausal women are characterized by higher lean body mass and elevated C-reactive protein. Although counterintuitive, we hypothesized that losses in muscle mass following caloric restriction and increase in muscle quality will be associated with improvements in glucose homeostasis through dec...

Postmenopausal women, despite their increased cardiovascular risk, do not meet physical activity recommendations. Outdoor exercise bouts induce more positive affective responses than the same indoor exercise. Outdoor training could therefore increase exercise adherence. This study aims to compare the long-term effects of outdoor and indoor training...

La réduction d’activité centrale du transmetteur sérotonine avec l’âge pourrait contribuer aux changements relatifs au sommeil chez l’aîné. Bien que l’effet bénéfique de l’exercice aérobie sur le sommeil ne soit pas nouveau, cet état d’inconscience récurrent et complexe implique plusieurs transmetteurs et ne demeure compris que partiellement malgré...

Aging is associated with noticeable impairments in brain serotonin transmission, which might contribute to increased vulnerability to developing depression in later life. Animal and human studies have shown that aerobic exercise can stimulate brain serotonin activity and trigger parallel elevations in tryptophan (TRP, the serotonin precursor) avail...

The objective of this systematic review was to appraise current knowledge on the impact of physical activity (PA) and physical fitness (PF) on the health of class II and III obese subjects and bariatric surgery (BS) patients. All original studies were searched using four databases (Medline®, Scopus®, CINAHL and Sportdiscus). Two independent investi...

Contribute evidence towards the complex interrelationships of body composition, physical performance and physical activity (PA) in an older population to assist in decisions for maintaining functional capacity in older adults. This is a cross-sectional analysis of an existing dataset in which a literature-supported model linking together the variab...