Combination Of High-intensity Interval Training And Moderate-intensity Continuous Exercise On Cardio-metabolic Responses In Physically Inactive Middle-aged Adults

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.

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Post-Exercise Appetite and Ad Libitum Energy Intake in Response to High-Intensity Interval Training versus Moderate- or Vigorous-Intensity Continuous Training among Physically Inactive Middle-Aged Adults

Nutrients ◽

10.3390/nu10101408 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1408 ◽

Cited By ~ 2

Author(s):

Eric Poon ◽

Feng-Hua Sun ◽

Anthony Chung ◽

Stephen Wong

Keyword(s):

Energy Intake ◽

Interval Training ◽

High Intensity Interval Training ◽

Middle Aged ◽

Continuous Training ◽

Post Exercise ◽

Ad Libitum ◽

High Intensity Interval ◽

Middle Aged Adults ◽

Physically Inactive

High-intensity interval training (HIIT) is considered a time-efficient exercise strategy for weight management. However, data regarding the acute appetite and energy intake responses to HIIT versus continuous training remain inconclusive. This study investigated the ad libitum energy intake and appetite responses to a single session of HIIT versus moderate-intensity continuous training (MICT) and vigorous-intensity continuous training (VICT). Using a randomized crossover design, 11 middle-aged physically inactive men (45.7 ± 7.4 years, 23.5 ± 2.1 kg m−2) participated in three treadmill trials at 7-day intervals. HIIT comprised 10 1-min periods at 100% VO2max interspersed with 1-min periods of active recovery. MICT comprised a 40-min session at 65% VO2max, while VICT comprised a 20-min session at 80% VO2max. After each trial, the participants consumed an ad libitum buffet meal for which the energy intake was recorded. The participants’ perceived appetite was assessed before and after exercise sessions using the Visual Analogue Scale (VAS). No significant differences in post-exercise ad libitum energy intake were observed between trials (HIIT: 645 ± 262.9 kcal; MICT: 614.7 ± 271.2 kcal; VICT: 623.1 ± 249.0 kcal, p > 0.05). Although the perceived appetite responses exhibited a significant main effect of time (p < 0.01), no group differences were observed (p > 0.05). In summary, these findings suggest that the interval or continuous nature of exercise has no significant effect on appetite responses in physically inactive middle-aged adults, at least during the short-term post-exercise period.

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