scholarly journals Acute RyR1 Ca2+ leak enhances NADH-linked mitochondrial respiratory capacity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nadège Zanou ◽  
Haikel Dridi ◽  
Steven Reiken ◽  
Tanes Imamura de Lima ◽  
Chris Donnelly ◽  
...  

AbstractSustained ryanodine receptor (RyR) Ca2+ leak is associated with pathological conditions such as heart failure or skeletal muscle weakness. We report that a single session of sprint interval training (SIT), but not of moderate intensity continuous training (MICT), triggers RyR1 protein oxidation and nitrosylation leading to calstabin1 dissociation in healthy human muscle and in in vitro SIT models (simulated SIT or S-SIT). This is accompanied by decreased sarcoplasmic reticulum Ca2+ content, increased levels of mitochondrial oxidative phosphorylation proteins, supercomplex formation and enhanced NADH-linked mitochondrial respiratory capacity. Mechanistically, (S-)SIT increases mitochondrial Ca2+ uptake in mouse myotubes and muscle fibres, and decreases pyruvate dehydrogenase phosphorylation in human muscle and mouse myotubes. Countering Ca2+ leak or preventing mitochondrial Ca2+ uptake blunts S-SIT-induced adaptations, a result supported by proteomic analyses. Here we show that triggering acute transient Ca2+ leak through RyR1 in healthy muscle may contribute to the multiple health promoting benefits of exercise.

Obesities ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 72-87
Author(s):  
Alexis Marcotte-Chénard ◽  
Dominic Tremblay ◽  
Marie-Michelle Mony ◽  
Pierre Boulay ◽  
Martin Brochu ◽  
...  

Objective: To compare the acute and chronic effects of low-volume high-intensity interval training (HIIT) to moderate-intensity continuous training (MICT) on glycemic control, body composition and continuous glucose monitoring (CGM) in older women with type 2 diabetes (T2D). Methods: Thirty older women (68 ± 5 years) with T2D were randomized in two groups—HIIT (75 min/week) or MICT (150 min/week). Glucose homeostasis (A1c, glucose, insulin, HOMA-IR2) and body composition (iDXA) were measured before and after the 12-week exercise intervention. During the first and last week of training (24-h before and 48-h after exercise), the following CGM-derived data were measured: 24-h and peak glucose levels, glucose variability and time spent in hypoglycemia as well as severe and mild hyperglycemia. Results: While lean body mass increased (p = 0.035), total and trunk fat mass decreased (p ≤ 0.007), without any difference between groups (p ≥ 0.81). Fasting glucose levels (p = 0.001) and A1c (p = 0.014) significantly improved in MICT only, with a significant difference between groups for fasting glucose (p = 0.02). Neither HIIT nor MICT impacted CGM-derived data at week 1 (p ≥ 0.25). However, 24-h and peak glucose levels, as well as time spent in mild hyperglycemia, decreased in HIIT at week 12 (p ≤ 0.03). Conclusion: These results suggest that 12 weeks of low-volume HIIT is enough to provide similar benefit to MICT for body composition and improve the acute effect of exercise when measured with CGM.


Author(s):  
Neumir Sales de Lima ◽  
Ricardo Augusto Leoni De Sousa ◽  
Fabiano Trigueiro Amorim ◽  
Fernando Gripp ◽  
Caíque Olegário Diniz e Magalhães ◽  
...  

Author(s):  
Abdullah Alansare ◽  
Ken Alford ◽  
Sukho Lee ◽  
Tommie Church ◽  
Hyun Jung

Physically inactive adults are prevalent worldwide. This study compared the effects of short-term high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on heart rate variability (HRV) in physically inactive adults as a preliminary study. Thirteen physically inactive male adults (27.5 ± 3.80 years) were randomly assigned to HIIT (N = 7) or MICT (N = 6). The HIIT program consisted of 20 min of interval training with cycling to rest ratio of 10/50 s at ≥90% HRpeak, while the MICT program consisted of 40 min of continuous cycling at 60–75% HRpeak. Both groups completed eight sessions of training within two weeks. Time and frequency domains of HRV were measured for 20 min with Actiwave-Cardio monitor (CamNtech, UK). The number of R-R interval and inter-beat interval (IBI) were significantly improved (p < 0.05) in both HIIT and MICT programs following eight sessions of training. A significant interaction effect for group by time was found in the lnLF/HF ratio (p < 0.05) where it was only improved in the HIIT group from pre- to post-test. The HIIT program is superior to MICT in improving HRV in physically inactive adults. The HIIT program can be applied as a time-efficient program for improving cardiac-autoregulation.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lauren E. Skelly ◽  
Celine Bailleul ◽  
Jenna B. Gillen

AbstractInterval training is a form of exercise that involves intermittent bouts of relatively intense effort interspersed with periods of rest or lower-intensity exercise for recovery. Low-volume high-intensity interval training (HIIT) and sprint interval training (SIT) induce physiological and health-related adaptations comparable to traditional moderate-intensity continuous training (MICT) in healthy adults and those with chronic disease despite a lower time commitment. However, most studies within the field have been conducted in men, with a relatively limited number of studies conducted in women cohorts across the lifespan. This review summarizes our understanding of physiological responses to low-volume interval training in women, including those with overweight/obesity or type 2 diabetes, with a focus on cardiorespiratory fitness, glycemic control, and skeletal muscle mitochondrial content. We also describe emerging evidence demonstrating similarities and differences in the adaptive response between women and men. Collectively, HIIT and SIT have consistently been demonstrated to improve cardiorespiratory fitness in women, and most sex-based comparisons demonstrate similar improvements in men and women. However, research examining insulin sensitivity and skeletal muscle mitochondrial responses to HIIT and SIT in women is limited and conflicting, with some evidence of blunted improvements in women relative to men. There is a need for additional research that examines physiological adaptations to low-volume interval training in women across the lifespan, including studies that directly compare responses to MICT, evaluate potential mechanisms, and/or assess the influence of sex on the adaptive response. Future work in this area will strengthen the evidence-base for physical activity recommendations in women.


2018 ◽  
Vol 30 (1) ◽  
pp. 38-41
Author(s):  
Keith Tolfrey ◽  
Julia Kirstey Zakrzewski-Fruer ◽  
Alice Emily Thackray

Two publications were selected because they are excellent representations of studies examining different ends of the exercise-sedentary behavior continuum in young people. The first study is an acute response study with 13 mixed-sex, mid to late adolescents presenting complete data from 4 different randomized experimental crossover conditions for analyses. Continuous glucose monitoring showed that interrupting prolonged continuous sitting with body-weight resistance exercises reduced the postprandial glucose concentration compared with a time-matched uninterrupted period of sitting. Furthermore, the effects of the breaks in sitting time were independent of the energy content of the standardized meals, but variations in the area under the glucose time curves expression were important. The second study adopted a chronic 12-week exercise training intervention design with a large sample of obese children and adolescents who were allocated randomly to high-intensity interval training (HIIT), moderate-intensity continuous training, or nutritional advice groups. HIIT was the most efficacious for improving cardiorespiratory fitness compared with the other interventions; however, cardiometabolic biomarkers and visceral/subcutaneous adipose tissue did not change meaningfully in any group over the 12 weeks. Attrition rates from both HIIT and moderate-intensity continuous training groups reduce the validity of the exercise training comparison, yet this still provides a solid platform for future research comparisons using HIIT in young people.


Author(s):  
Sigbjørn Litleskare ◽  
Eystein Enoksen ◽  
Marit Sandvei ◽  
Line Støen ◽  
Trine Stensrud ◽  
...  

The purpose of the present study was to investigate training-specific adaptations to eight weeks of moderate intensity continuous training (CT) and sprint interval training (SIT). Young healthy subjects (n = 25; 9 males and 16 females) performed either continuous training (30–60 min, 70–80% peak heart rate) or sprint interval training (5–10 near maximal 30 s sprints, 3 min recovery) three times per week for eight weeks. Maximal oxygen consumption, 20 m shuttle run test and 5·60 m sprint test were performed before and after the intervention. Furthermore, heart rate, oxygen pulse, respiratory exchange ratio, lactate and running economy were assessed at five submaximal intensities, before and after the training interventions. Maximal oxygen uptake increased after CT (before: 47.9 ± 1.5; after: 49.7 ± 1.5 mL·kg−1·min−1, p < 0.05) and SIT (before: 50.5 ± 1.6; after: 53.3 ± 1.5 mL·kg−1·min−1, p < 0.01), with no statistically significant differences between groups. Both groups increased 20 m shuttle run performance and 60 m sprint performance, but SIT performed better than CT at the 4th and 5th 60 m sprint after the intervention (p < 0.05). At submaximal intensities, CT, but not SIT, reduced heart rate (p < 0.05), whereas lactate decreased in both groups. In conclusion, both groups demonstrated similar improvements of several performance measures including VO2max, but sprint performance was better after SIT, and CT caused training-specific adaptations at submaximal intensities.


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