Martin Gibala

Sprint interval training (SIT) increases peak oxygen uptake (V̇O2peak ) but the mechanistic basis is unclear. We have reported that 12 wk of SIT increased V̇O2peak and peak cardiac output (Q̇peak ) and the changes in these variables were correlated. An exploratory analysis suggested that Q̇peak increased in males but not females. The present study incorporated best practices to examine the potential influence of biological sex on the Q̇peak response to SIT. Male and female participants (n = 10 each; 21 ± 4 y) performed 33 ± 2 sessions of SIT over 12 wk...

Vigorous intermittent exercise can improve indices of glycemia in the 24 h postexercise period in apparently healthy individuals. We examined the effect of a single session of bodyweight exercise (BWE) on glycemic responses using continuous glucose monitoring (CGM) under controlled dietary conditions. Healthy inactive adults (n = 27; 8 males, 19 females; age: 23 ± 3 years) completed 2 virtually supervised trials spaced ~ 1 week apart in a randomized, crossover manner...

BACKGROUND: Mild cognitive impairment (MCI) is a syndrome preceding more severe impairment characterized by dementia. MCI affects an estimated 15% to 20% of people older than 65 years. Nonpharmacological interventions including exercise are recommended as part of overall MCI management based on the positive effects of exercise on cognitive performance. Interval training involves brief intermittent bouts of exercise interspersed with short recovery periods. This type of exercise promotes cognitive improvement and can be performed in individuals with MCI...

Interval training is a simple concept that refers to repeated bouts of relatively hard work interspersed with recovery periods of easier work or rest. The method has been used by high-level athletes for over a century to improve performance in endurance-type sports and events such as middle- and long-distance running. The concept of interval training to improve health, including in a rehabilitative context or when practiced by individuals who are relatively inactive or deconditioned, has also been advanced for decades...

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BACKGROUND: Previous research has identified sex differences in substrate oxidation during submaximal aerobic exercise including a lower respiratory exchange ratio (RER) in females compared to males. These differences may be related to differences in sex hormones. Our purpose was to examine the impact of the natural menstrual cycle (NAT) and 2nd and 3rd generation oral contraceptive pill (OCP2, OCP3) cycle phases on substrate oxidation during rest and submaximal aerobic exercise. METHODS: Fifty female participants (18 NAT, 17 OCP2, 15 OCP3) performed two experimental trials that coincided with the low (i...

Acute ketone monoester (KE) supplementation can alter exercise responses, but the performance effect is unclear. The limited and equivocal data to date are likely related to factors including the KE dose, test conditions, and caliber of athletes studied. We tested the hypothesis that mean power output during a 20-min cycling time trial (TT) would be different after KE ingestion compared to a placebo (PL). A sample size of 22 was estimated to provide 80% power to detect an effect size dz of 0.63 at an alpha level of ...

PURPOSE: To examine the effect of KE ingestion on exercise cardiac output (Q̇) and the influence of blood acidosis. We hypothesized that KE vs placebo ingestion would increase Q̇ and co-ingestion of the pH buffer bicarbonate would mitigate this effect. METHODS: In a randomized, double-blind, crossover manner, 15 endurance-trained adults [peak oxygen uptake (V̇O2peak), 60 ± 9 mL/kg/min] ingested either 0.2 g/kg sodium bicarbonate or a salt placebo 60-min pre-exercise, and 0...

There is renewed interest in the potential for interval (INT) training to increase skeletal muscle mitochondrial content including whether the response differs from continuous (CONT) training. Comparisons of INT and CONT exercise are impacted by the manner in which protocols are "matched", particularly with respect to exercise intensity, as well as inter-individual differences in training responses. We employed single-leg cycling to facilitate a within-participant design and test the hypothesis that short-term INT training would elicit a greater increase in mitochondrial content than work- and intensity-matched CONT training...

PURPOSE: To compare Q̇peak elicited by a constant load protocol (Q̇CL) and an incremental step protocol (Q̇step). METHODS: A non-inferiority randomized crossover trial was used to compare Q̇peak between protocols using a non-inferiority margin of 0.5 L/min. Participants [n = 34 (19 females, 15 males); 25 ± 5 y] performed two baseline V̇O2peak tests to determine peak heart rate (HRpeak) and peak work rate (Wpeak). Participants then performed the Q̇CL and Q̇step protocols each on two separate occasions with the order of the four visits randomized...

Wearable devices can capture unexplored movement patterns such as brief bursts of vigorous intermittent lifestyle physical activity (VILPA) that is embedded into everyday life, rather than being done as leisure time exercise. Here, we examined the association of VILPA with all-cause, cardiovascular disease (CVD) and cancer mortality in 25,241 nonexercisers (mean age 61.8 years, 14,178 women/11,063 men) in the UK Biobank. Over an average follow-up of 6.9 years, during which 852 deaths occurred, VILPA was inversely associated with all three of these outcomes in a near-linear fashion...

Brief, intense interval training describes a style of exercise characterized by short bouts of strenuous effort interspersed with recovery periods. The method increases whole body maximal oxygen uptake (V̇o2max ), but the underlying physiological basis is unclear. V̇o2max represents the functional limit of the integrative oxygen cascade, which refers to the physiological steps involved in oxygen transport and utilization from atmospheric air to mitochondrial metabolism. There is insufficient evidence to definitively state which steps in the oxygen cascade are responsible for the improvement in V̇o2max after brief, intense interval training...

Exercise-based cardiac rehabilitation leads to improvements in cardiovascular function in individuals with coronary artery disease. The cardiac effects of coronary artery disease (CAD) can be quantified using clinical echocardiographic measures, such as ejection fraction (EF). Measures of cardiovascular function typically only used in research settings can provide additional information and maybe more sensitive indices to assess changes after exercise-based cardiac rehabilitation. These additional measures include endothelial function (measured by flow-mediated dilation), left ventricular twist, myocardial performance index, and global longitudinal strain...

BACKGROUND: High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) alone has been shown to improve metabolic health, but the effects of alternating the two training approaches as often practiced in real life remained unclear. PURPOSE: To examine the effects of HIIT or MICT alone or alternating HIIT-MICT on cardiometabolic responses in inactive obese middle-aged men. METHODS: Forty-two participants (age: 42 ± 5 y; BMI: 26...

We define exercise snacks as isolated ≤1-min bouts of vigorous exercise performed periodically throughout the day. We hypothesize that exercise snacks are a feasible, well-tolerated, and time-efficient approach to improve cardiorespiratory fitness and reduce the negative impact of sedentary behavior on cardiometabolic health. Efficacy has been demonstrated in small proof-of-concept studies. Additional research should investigate this novel physical activity strategy.

Bodyweight training (BWT) is a style of interval exercise based on classic principles of physical education. Limited research, however, has examined the efficacy of BWT on cardiorespiratory fitness. This is especially true for simple BWT protocols that do not require extraordinarily high levels of effort. We examined the effect of a BWT protocol, modelled after the original "Five Basic Exercises" (5BX) plan, on peak oxygen uptake (VO2peak ) in healthy, inactive adults (20 ± 1 y; body mass index: 20 ± 5 kg/m2 ; mean ± SD)...

INTRODUCTION: Sprint interval training (SIT), characterized by brief bouts of 'supramaximal' exercise interspersed with recovery periods, increases peak oxygen uptake ([Formula: see text]) despite a low total exercise volume. Per the Fick principle, increased [Formula: see text] is attributable to increased peak cardiac output ([Formula: see text]) and/or peak arterio-venous oxygen difference (a-vO2diff ). There are limited and equivocal data regarding the physiological basis for SIT-induced increases in [Formula: see text], with most studies lasting ≤ 6 weeks...

Background: Cardiac rehabilitation exercise reduces the risk of secondary cardiovascular disease. Interval training is a time-efficient alternative to traditional cardiac rehabilitation exercise and stair climbing is an accessible means. We aimed to assess the effectiveness of a high-intensity interval stair climbing intervention on improving cardiorespiratory fitness ( <mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mtext>V</mml:mtext> <mml:mo>˙</mml:mo> </mml:mover> <mml:msub> <mml:mtext>O</mml:mtext> <mml:mrow> <mml:mn>2</mml:mn> <mml:mtext>peak</mml:mtext> </mml:mrow> </mml:msub> </mml:math> ) compared to standard cardiac rehabilitation care...

There is growing interest in the effect of exogenous ketone body supplementation on exercise responses and performance. The limited studies to date have yielded equivocal data, likely due in part to differences in dosing strategy, increase in blood ketones, and participant training status. Using a randomized, double-blind, counterbalanced design, we examined the effect of ingesting a ketone monoester (KE) supplement (600 mg/kg body mass) or flavour-matched placebo in endurance-trained adults ( n = 10 males, n = 9 females; V̇ O2peak = 57 ± 8 mL/kg/min)...

There are limited and equivocal data regarding potential fiber type-specific differences in the human skeletal muscle response to sprint interval training (SIT), including how this compares with moderate-intensity continuous training (MICT). We examined mixed-muscle and fiber type-specific responses to a single session ( study 1 ) and to 12 wk ( study 2 ) of MICT and SIT using Western blot analysis. MICT consisted of 45 min of cycling at ∼70% of maximal heart rate, and SIT involved 3 × 20-s "all-out" sprints interspersed with 2 min of recovery...