Durability is improved by both low and high intensity endurance training

Pekka Matomäki; Olli J Heinonen; Ari Nummela; Jari Laukkanen; Eero-Pekka Auvinen; Leena Pirkola; Heikki Kyröläinen

doi:10.3389/fphys.2023.1128111

Durability is improved by both low and high intensity endurance training

Front Physiol. 2023 Feb 16:14:1128111. doi: 10.3389/fphys.2023.1128111. eCollection 2023.

Authors

Pekka Matomäki^{1

2}, Olli J Heinonen², Ari Nummela³, Jari Laukkanen^{4

5}, Eero-Pekka Auvinen¹, Leena Pirkola¹, Heikki Kyröläinen¹

Affiliations

¹ Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
² Paavo Nurmi Centre & Unit for Health and Physical Activity, University of Turku, Turku, Finland.
³ Finnish Institute of High Performance Sport KIHU, Jyväskylä, Finland.
⁴ Central Finland Healthcare District, Department of Medicine, Jyväskylä, Finland.
⁵ Department of Medicine, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.

Abstract

Introduction: This is one of the first intervention studies to examine how low- (LIT) and high-intensity endurance training (HIT) affect durability, defined as 'time of onset and magnitude of deterioration in physiological-profiling characteristics over time during prolonged exercise'. Methods: Sedentary and recreationally active men (n = 16) and women (n = 19) completed either LIT (average weekly training time 6.8 $\pm$ 0.7 h) or HIT (1.6 $\pm$ 0.2 h) cycling for 10 weeks. Durability was analyzed before and after the training period from three factors during 3-h cycling at 48% of pretraining maximal oxygen uptake (VO_2max): 1) by the magnitude and 2) onset of drifts (i.e. gradual change in energy expenditure, heart rate, rate of perceived exertion, ventilation, left ventricular ejection time, and stroke volume), 3) by the 'physiological strain', defined to be the absolute responses of heart rate and its variability, lactate, and rate of perceived exertion. Results: When all three factors were averaged the durability was improved similarly (time x group p = 0.42) in both groups (LIT: p = 0.03, g = 0.49; HIT: p = 0.01, g = 0.62). In the LIT group, magnitude of average of drifts and their onset did not reach statistically significance level of p < 0.05 (magnitude: 7.7 $\pm$ 6.8% vs. 6.3 $\pm$ 6.0%, p = 0.09, g = 0.27; onset: 106 $\pm$ 57 min vs. 131 $\pm$ 59 min, p = 0.08, g = 0.58), while averaged physiological strain improved (p = 0.01, g = 0.60). In HIT, both magnitude and onset decreased (magnitude: 8.8 $\pm$ 7.9% vs. 5.4 $\pm$ 6.7%, p = 0.03, g = 0.49; onset: 108 $\pm$ 54 min vs. 137 $\pm$ 57 min, p = 0.03, g = 0.61), and physiological strain improved (p = 0.005, g = 0.78). VO_2max increased only after HIT (time x group p < 0.001, g = 1.51). Conclusion: Durability improved similarly by both LIT and HIT based on reduced physiological drifts, their postponed onsets, and changes in physiological strain. Despite durability enhanced among untrained people, a 10-week intervention did not alter drifts and their onsets in a large amount, even though it attenuated physiological strain.

Keywords: cardiovascular drift; durability; high intensity training; low intensity training; perceived exertion.

Grants and funding

Heart rate monitors, power meters, and salary for two research assistants were received from Firstbeat Analytics. Firstbeat Analytics received data from the research measurements, and it does not benefit from the results of the present study.