Low- and High-Volume of Intensive Endurance Training Significantly Improves Maximal Oxygen Uptake after 10-Weeks of Training in Healthy Men

Arnt Erik Tjønna,Martin J Gibala,Richard A Winett,Bjørn M Jenssen,Ingeborg Megaard Leinan,Anette Thoresen Bartnes,Ulrik Wisløff,Conrad P Earnest

doi:10.1371/journal.pone.0065382

Arnt Erik Tjønna, Martin J Gibala + Show 6 more

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https://doi.org/10.1371/journal.pone.0065382

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Abstract

Regular exercise training improves maximal oxygen uptake (VO2max), but the optimal intensity and volume necessary to obtain maximal benefit remains to be defined. A growing body of evidence suggests that exercise training with low-volume but high-intensity may be a time-efficient means to achieve health benefits. In the present study, we measured changes in VO2max and traditional cardiovascular risk factors after a 10 wk. training protocol that involved three weekly high-intensity interval sessions. One group followed a protocol which consisted of 4×4 min at 90% of maximal heart rate (HRmax) interspersed with 3 min active recovery at 70% HRmax (4-AIT), the other group performed a single bout protocol that consisted of 1×4 min at 90% HRmax (1-AIT). Twenty-six inactive but otherwise healthy overweight men (BMI: 25–30, age: 35–45 y) were randomized to either 1-AIT (n = 11) or 4-AIT (n = 13). After training, VO2max increased by 10% (∼5.0 mL⋅kg−1⋅min−1) and 13% (∼6.5 mL⋅kg−1⋅min−1) after 1-AIT and 4-AIT, respectively (group difference, p = 0.08). Oxygen cost during running at a sub-maximal workload was reduced by 14% and 13% after 1-AIT and 4-AIT, respectively. Systolic blood pressure decreased by 7.1 and 2.6 mmHg after 1-AIT and 4-AIT respectively, while diastolic pressure decreased by 7.7 and 6.1 mmHg (group difference, p = 0.84). Both groups had a similar ∼5% decrease in fasting glucose. Body fat, total cholesterol, LDL-cholesterol, and ox-LDL cholesterol only were significantly reduced after 4-AIT. Our data suggest that a single bout of AIT performed three times per week may be a time-efficient strategy to improve VO2max and reduce blood pressure and fasting glucose in previously inactive but otherwise healthy middle-aged individuals. The 1-AIT type of exercise training may be readily implemented as part of activities of daily living and could easily be translated into programs designed to improve public health.Trial Registration ClinicalTrials.gov NCT00839579

Highlights

The global epidemic of overweight [body mass index (BMI) between 25.0–29.9] and obesity (BMI$30) has become a major health, social and economic burden
Despite randomization, there was a tendency for higher body mass in 1-AIT when compared to 4-AIT (Table 1)
Work economy improved by 14% (26.9 (210.0, 23.9)) and 13% [26.4 (29.2, 23.6) after 1-AIT and 4-AIT, respectively, Figure 2C]

Summary

Introduction

The global epidemic of overweight [body mass index (BMI) between 25.0–29.9] and obesity (BMI$30) has become a major health, social and economic burden. Lee et al [8] showed that apparently healthy elderly men who exercised once or twice per week (so-called ‘‘weekend warriors’’) had a lower risk of all-cause mortality compared with sedentary counterparts. Consistent with these findings, a 18-year follow-up study revealed that a single, vigorous weekly bout of physical activity was associated with prevention of cardiovascular death among men and woman without known cardiovascular disease at the beginning of followup [9]. These data suggest that it may be possible to reduce cardiovascular mortality with substantially less exercise than is generally recommended, provided it is performed in a vigorous manner [10]

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