TY - JOUR
T1 - High-intensity aerobic, but not resistance or combined, exercise training improves both cardiometabolic health and skeletal muscle mitochondrial dynamics
AU - Ruegsegger, Gregory N.
AU - Pataky, Mark W.
AU - Simha, Suvyaktha
AU - Robinson, Matthew M.
AU - Klaus, Katherine A.
AU - Nair, K. Sreekumaran
N1 - Publisher Copyright:
© 2023 the American Physiological Society.
PY - 2023
Y1 - 2023
N2 - This study investigated how different exercise training modalities influence skeletal muscle mitochondrial dynamics. Healthy [average body mass index (BMI): 25.8 kg/m2], sedentary younger and older participants underwent 12 wk of supervised high-intensity aerobic interval training (HIIT; n ¼ 13), resistance training (RT; n ¼ 14), or combined training (CT; n ¼ 11). Mitochondrial structure was assessed using transmission electron microscopy (TEM). Regulators of mitochondrial fission and fusion, cardiorespiratory fitness (V_ O2peak), insulin sensitivity via a hyperinsulinemic-euglycemic clamp, and muscle mitochondrial respiration were assessed. TEM showed increased mitochondrial volume, number, and perimeter following HIIT (P < 0.01), increased mitochondrial number following CT (P < 0.05), and no change in mitochondrial abundance after RT. Increased mitochondrial volume associated with increased mitochondrial respiration and insulin sensitivity following HIIT (P < 0.05). Increased mitochondrial perimeter associated with increased mitochondrial respiration, insulin sensitivity, and V_ O2peak following HIIT (P < 0.05). No such relationships were observed following CT or RT. OPA1, a regulator of fusion, was increased following HIIT (P < 0.05), whereas FIS1, a regulator of fission, was decreased following HIIT and CT (P < 0.05). HIIT also increased the ratio of OPA1/FIS1 (P < 0.01), indicative of the balance between fission and fusion, which positively correlated with improvements in respiration, insulin sensitivity, and V_ O2peak (P < 0.05). In conclusion, HIIT induces a larger, more fused mitochondrial tubular network. Changes indicative of increased fusion following HIIT associate with improvements in mitochondrial respiration, insulin sensitivity, and V_ O2peak supporting the idea that enhanced mitochondrial fusion accompanies notable health benefits of HIIT.
AB - This study investigated how different exercise training modalities influence skeletal muscle mitochondrial dynamics. Healthy [average body mass index (BMI): 25.8 kg/m2], sedentary younger and older participants underwent 12 wk of supervised high-intensity aerobic interval training (HIIT; n ¼ 13), resistance training (RT; n ¼ 14), or combined training (CT; n ¼ 11). Mitochondrial structure was assessed using transmission electron microscopy (TEM). Regulators of mitochondrial fission and fusion, cardiorespiratory fitness (V_ O2peak), insulin sensitivity via a hyperinsulinemic-euglycemic clamp, and muscle mitochondrial respiration were assessed. TEM showed increased mitochondrial volume, number, and perimeter following HIIT (P < 0.01), increased mitochondrial number following CT (P < 0.05), and no change in mitochondrial abundance after RT. Increased mitochondrial volume associated with increased mitochondrial respiration and insulin sensitivity following HIIT (P < 0.05). Increased mitochondrial perimeter associated with increased mitochondrial respiration, insulin sensitivity, and V_ O2peak following HIIT (P < 0.05). No such relationships were observed following CT or RT. OPA1, a regulator of fusion, was increased following HIIT (P < 0.05), whereas FIS1, a regulator of fission, was decreased following HIIT and CT (P < 0.05). HIIT also increased the ratio of OPA1/FIS1 (P < 0.01), indicative of the balance between fission and fusion, which positively correlated with improvements in respiration, insulin sensitivity, and V_ O2peak (P < 0.05). In conclusion, HIIT induces a larger, more fused mitochondrial tubular network. Changes indicative of increased fusion following HIIT associate with improvements in mitochondrial respiration, insulin sensitivity, and V_ O2peak supporting the idea that enhanced mitochondrial fusion accompanies notable health benefits of HIIT.
KW - fission
KW - fusion
KW - HIIT
KW - mitochondria
KW - resistance exercise
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U2 - 10.1152/JAPPLPHYSIOL.00405.2023
DO - 10.1152/JAPPLPHYSIOL.00405.2023
M3 - Article
C2 - 37616334
AN - SCOPUS:85171900546
SN - 8750-7587
VL - 135
SP - 763
EP - 774
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 4
ER -