Novel all-extremity high-intensity interval training improves aerobic fitness, cardiac function and insulin resistance in healthy older adults

• Published in: Experimental gerontology Vol. 82; pp. 112 - 119
• Main Authors: Hwang, Chueh-Lung, Yoo, Jeung-Ki, Kim, Han-Kyul, Hwang, Moon-Hyon, Handberg, Eileen M., Petersen, John W., Christou, Demetra D.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.09.2016
• Subjects: Aerobic fitness; Aged; Aging; Aging - physiology; Body Composition; Cardiac function; Cardiorespiratory Fitness; Female; Florida; Healthy Volunteers; Heart Rate; High-intensity interval training; High-Intensity Interval Training - methods; Humans; Insulin Resistance; Linear Models; Male; Metabolic risk factors; Middle Aged; Moderate-intensity continuous training; Oxygen Consumption; Risk Factors; Weight-Bearing; High-intensity interval training; Aging; Metabolic risk factors; Moderate-intensity continuous training; Cardiac function; Aerobic fitness
• ISSN: 0531-5565; 1873-6815
• DOI: 10.1016/j.exger.2016.06.009

Aging is associated with decreased aerobic fitness and cardiac remodeling leading to increased risk for cardiovascular disease. High-intensity interval training (HIIT) on the treadmill has been reported to be more effective in ameliorating these risk factors compared with moderate-intensity continuous training (MICT) in patients with cardiometabolic disease. In older adults, however, weight-bearing activities are frequently limited due to musculoskeletal and balance problems. The purpose of this study was to examine the feasibility and safety of non-weight-bearing all-extremity HIIT in older adults. In addition, we tested the hypothesis that all-extremity HIIT will be more effective in improving aerobic fitness, cardiac function, and metabolic risk factors compared with all-extremity MICT. Fifty-one healthy sedentary older adults (age: 65±1years) were randomized to HIIT (n=17), MICT (n=18) or non-exercise control (CONT; n=16). HIIT (4×4min 90% of peak heart rate; HRpeak) and isocaloric MICT (70% of HRpeak) were performed on a non-weight-bearing all-extremity ergometer, 4×/week for 8weeks under supervision. All-extremity HIIT was feasible in older adults and resulted in no adverse events. Aerobic fitness (peak oxygen consumption; VO2peak) and ejection fraction (echocardiography) improved by 11% (P<0.0001) and 4% (P=0.001), respectively in HIIT, while no changes were observed in MICT and CONT (P≥0.1). Greater improvements in ejection fraction were associated with greater improvements in VO2peak (r=0.57; P<0.0001). Insulin resistance (homeostatic model assessment) decreased only in HIIT by 26% (P=0.016). Diastolic function, body composition, glucose and lipids were unaffected (P≥0.1). In conclusion, all-extremity HIIT is feasible and safe in older adults. HIIT, but not MICT, improved aerobic fitness, ejection fraction, and insulin resistance. •All-extremity high-intensity interval training (HIIT) is feasible in older adults.•HIIT over 8weeks is safe and resulted in no adverse events.•HIIT improves aerobic fitness, ejection fraction, and insulin resistance.