Occupational physical activity, energy expenditure and 11-year progression of carotid atherosclerosis

Does aerobic exercise improve or impair cardiorespiratory fitness and health among cleaners? A cluster randomized controlled trial

“…Therefore, the null hypothesis of no effects is rejected for blood pressure. This finding is in accordance with the previously stated hypothesis of Krause and colleagues (22) that high intensity physical exercise may cause an overload of the cardiovascular system when applied to workers with high levels of occupational physical activity, low cardiorespiratory fitness, and potentially limited ability for pauses and restitution.…”

“…The aerobic workload measured at baseline was relatively high [31 (SE 7) %HRR]. Such high aerobic workload is reported to cause strain on the cardiovascular systems (11), potentially leading to progression of arteriosclerosis (5,6) and relates to an increased risk of cardiovascular disease (7,22). The observed reduction in aerobic workload of 11.3% can therefore be considered of clinical relevance.…”

“…Workers with high levels of occupational physical activity often have a low cardiorespiratory fitness (4,(24)(25)(26) and limited ability for pauses and restitution, which may result in an increased risk of overloading and impairing the cardiovascular system (22). Thus, an aerobic exercise intervention may affect factors for cardiovascular disease both positively and negatively.…”

“…Actually, it has been discussed in the literature, whether introducing aerobic exercise could overload and thereby impair the cardiovascular system among workers with high levels of occupational physical activity (22,23). Workers with high levels of occupational physical activity often have a low cardiorespiratory fitness (4,(24)(25)(26) and limited ability for pauses and restitution, which may result in an increased risk of overloading and impairing the cardiovascular system (22).…”

“…In fact, the extensive objective measurements revealed that more than half (51%) of our study population exceeded recommended levels of relative aerobic workload during working hours at baseline. Previous research has linked higher levels of aerobic workload with accelerated progression of atherosclerosis (22) and incidence of myocardial infarction (7). Clearly, there is a need to develop interventions that safely reduce aerobic workload and cardiovascular risk among high-risk occupational groups experiencing a high level of occupational physical activity (3).…”