Rethinking the dose response and risk-benefit relation for health benefits of exercise

Purpose: The dose response relationship between exercise and all-cause mortality has been well documented. The current Health and Human Services (HHS) guidelines recommend 150 minutes of moderate intensity exercise per week. This presents a barrier to entry for many patients, as demonstrated by nearly half of all Americans not meeting the HHS guidelines for daily aerobic activity. Methods: Using data from cohort studies, randomized control trials, and case control studies, we evaluated health outcomes at exercise volumes lower than the current recommendations. We used the 2011 Compendium of Physical Activities to quantify the contributions of daily activities and exercises to achieve activity level recommendations. Results: Despite current guidelines suggesting a minimum amount of 150 minutes of moderate intensity exercise to achieve benefit, we found there was statistically significant benefit occurring at much lower volumes of exercise. The largest change in overall mortality is often seen when comparing groups of no or minimal amounts of exercise to those engaging in low amounts of activity. This low level of energy expenditure can often be achieved without engaging in classical "exercise" regimens. Conclusion: The current exercise recommendations can challenge patients' time, resources, physical capability, and self-efficacy. While current guidelines emphasize 150 minutes of moderately intense activity per week, patients benefit from much lower weekly physical activity volumes. A reframing of what is considered exercise would allow patients to subjectively feel more confident in their ability to influence their health through movement. Patients can also be challenged by the specific recommendations of aerobic exercise. This may be remedied by guiding patients to consider daily, non-exercise modalities as sources of weekly activity. Ultimately, assessing the risk-benefit relation to total exercise workload may provide a novel approach to determining optimal targets for exercise that provide the safest and most efficacious exercise regimen. Therefore, clinical discussions focused on prescribing exercise should begin with acknowledgement of normal daily activities that promote energy expenditure and encouraging patients to increase overall weekly movement.