Exercise, illness and drug use: guiding principles for approaching a complex triad

Abstract

Regular, low to moderate intensity exercise is considered beneficial to the human body, not only having ergogenic advantages, but also being anti-inflammatory, cardio- and neuroprotective.¹ On the other hand, although high intensity training (HIT) is able to exaggerate cardiac conditions, e.g., hypertension² as well as exacerbate inflammatory and oxidative stress responses,^1,3 such exercise programs are becoming more popular as they too have shown demonstrable health benefits if performed appropriately. Indeed, various studies have reported on the superior beneficial cardiac and vascular effects of high intensity exercise programs over that of moderate intensity continuous training (MICT),^4-7 contributing to the growing popularity of such time-efficient programs. As such, exercise can accurately be described as a double-edged sword – able to induce positive, beneficial physiological effects when performed chronically at lower intensities, but generating harmful effects when performed at high intensities without sufficient recovery periods. From a toxicological point of view, exercise mediates hormesis, i.e., the biphasic dose response to an environmental agent characterised by a low dose stimulation or beneficial effect and a high dose inhibitory or toxic effect.⁸