High-intensity interval training on body composition, functional capacity and biochemical markers in healthy young versus older people

Highlights

• Aging produces morphofunctional and physiological changes.

• HIIT suggests it is beneficial as a comprehensive strategy for aging.

• HIIT has morphofunctional and physiological benefits in young and older adults.

• HIIT could be used to prevent the onset of sarcopenia in healthy older adults.

Abstract

Background

The aim of the following study was to identify the effects of a 12-week high-intensity interval training (HIIT) program on the modification of parameters of body composition, functional capacity as well as lipid and glucose homeostasis markers in healthy young people versus older adults.

Design

Experimental trial.

Methods

Healthy young (YNG, 21 ± 1 years, BMI 26.01 ± 2.64 kg·m^-2, n = 10) and older (OLD, 66 ± 5 years, BMI 27.43 ± 3.11 kg·m^-2, n = 10) males were subjected to 12 weeks of HIIT. Prior to and immediately after the HIIT program, dual-energy X-ray absorptiometry, dominant leg strength one-repetition maximum (1-RM), maximal oxygen uptake (VO_2max) and physical performance tests were performed. Blood samples were also taken.

Results

Flexibility (P = 0.000), static balance (P = 0.004), timed up and go test (TUG) (P = 0.015), short physical performance battery (SPPB) (P = 0.005), dominant leg strength 1-RM (P = 0.012), and VO_2max (P = 0.000) were better in YNG versus OLD. HIIT improved the % whole-body fat mass (P = 0.031), leg lean mass (P = 0.047), dominant leg strength 1-RM (P = 0.025), VO_2max (P = 0.000), fasting cholesterol (P = 0.017) and fasting glucose (P = 0.006). TUG was improved by the training only in the OLD group (P = 0.016), but insulin (P = 0.002) and the homeostasis model assessment - insulin sensitivity (HOMA-IS) (P = 0.000) decreased only in the YNG group. HOMA-IS was correlated positive with BMI (R = 0.474, P = 0.035) and with whole-body fat mass (R = 0.517, P = 0.019).

Conclusions

HIIT for 12 weeks improves parameters of body composition, functional capacity and fasting serum lipid and glucose homeostasis markers in healthy young and older participants. Young people are shown as benefiting more.

Introduction

Aging process is characterized by changes in body composition, being the decrease in skeletal muscle mass the main feature. This is part of the phenomenon called “sarcopenia” (Rosenberg, 1997). Its prevalence is ~25% around 70 years of age and increases to 40% at 80 years (Thompson, 2009). Multiple factors have been related to the etiology of sarcopenia, including skeletal muscle fiber atrophy, physical inactivity, high levels of pro-inflammatory cytokines, increased free radical production, decrease in the antioxidant defense system, malnutrition and low release of anabolic hormones (Giovannini et al., 2008). In addition, in older adults the skeletal muscle presents anabolic resistance, i.e., the anabolic response is attenuated to amino acids and/or resistance training (Churchward-Venne et al., 2014; Morton et al., 2018).

The strategies that are used to mitigate skeletal muscle atrophy due to aging include oral supplements, electrostimulation, mechanical loads and/or physical exercise (Dirks et al., 2015; Magne et al., 2013; Marzuca-Nassr et al., 2017; Wall and van Loon, 2013; Chodzko-Zajko et al., 2009; Mora and Valencia, 2018). The variables to consider in the volume of physical exercise applied are training intensity (work per time unit), duration (time per session) and frequency (sessions per week) (MacInnis and Gibala, 2017). High-intensity interval training (HIIT) is one of the various types of physical exercise and is characterized as short periods of high-intensity exercise accompanied by rest at intervals repeated over time (Mancilla et al., 2014; Robinson et al., 2017).

At the moment, great emphasis is being placed on the effects of HIIT on aging at the aerobic or muscle level separately. However, studies in animal and human models suggest that HIIT could be of comprehensive benefit (body composition, physical performance, oxidative stress and inflammation markers) to fighting the changes produced by aging (Robinson et al., 2017; Li et al., 2018).

It has been shown that HIIT as cardiometabolic exercise has benefits in young people and older adults on body weight, regulation of physiological parameters like blood pressure, increase in VO_2max, and reductions in glucose levels and triglycerides (Mancilla et al., 2014; Robinson et al., 2017; Grace et al., 2018; Herbert et al., 2017; Osawa et al., 2014; Sculthorpe et al., 2017). At muscle level, HIIT increases the cross-sectional area of quadriceps in healthy middle-aged adults (20–48 years of age) (Osawa et al., 2014) and diabetic middle-aged adults (45.4 ± 7.2) (Boudou et al., 2003). In this regard, there is evidence that HIIT produces an increase in in vivo myofibrillar and sarcoplasmic fractional synthetic rate in older adults (Bell et al., 2015), improves insulin resistance (Hwang et al., 2016), increases IGF-1 (Herbert et al., 2017) and increases fat-free mass and lower limb muscle power (Sculthorpe et al., 2017).

In light of all this information, the aim of the following study was to identify the effects of a 12-week HIIT program on the modification of parameters of body composition, functional capacity as well as fasting serum lipid and glucose homeostasis markers in healthy young people versus older adults.