Two major health challenges facing midlife adults in our society are chronic pain and insufficient physical activity (PA). Chronic pain is highly prevalent among females and those who previously engaged in substantial vigorous PA, such as former competitive athletes. Exercise (i.e., a specific planned subtype of PA) is one of the best interventions for optimizing health, maintaining function, and preserving cardiorespiratory fitness - yet ironically often not continued among midlife adults who were highly physically active as youth and young adults in competitive sports. While PA and other lifestyle behaviors (e.g., sleep) likely influence pain processing and response to exercise, the mechanisms underlying pain in males and females with distinct PA trajectories are unknown. Pain is a common and critical barrier to regular exercise. Yet exercise has paradoxical effects on pain, generally increasing pain during exercise and providing pain relief after, i.e., exercise-induced hypoalgesia. While higher exercise intensities may lead to greater exercise-induced hypoalgesia, the greater pain and discomfort experienced during high-intensity exercise may prevent uptake, making moderate-intensity exercise a promising solution balancing physiological benefits and exercise-induced hypoalgesia. The investigators' long-term objective is to alleviate pain, increase PA, and improve health in midlife and aging adults. This randomized crossover clinical trial will determine how markedly different PA trajectories and sex influence pain, lifestyle behaviors, and the pain response to exercise (exercise-induced hypoalgesia). Given that pain is affected by PA and sports history, this proposal will examine pain processing in midlife males and females with distinct PA trajectories evenly split across 3 unique groups: 1) former athletes no longer participating in sports; 2) master's athletes; and 3) nonathletes.
In order to compare pain perceptions and processing in former athletes, master's athletes, and nonathletes, quantitative sensory testing and validated questionnaires will be used. Lifestyle behaviors (PA and sleep) will be assessed using wearable devices. Moderate-intensity strength and aerobic exercise interventions will be included to determine how these influence the pain perceptions of former athletes, current master's athletes and nonathletes. Full participation will involve completing three in-person sessions including baseline assessment session and two intervention sessions (i.e., follow-up 1 and follow-up 2 at approximately 1 week intervals) at Marquette University as well as wearing a small physical activity monitor for 2 weeks following baseline session and an OURA ring for the duration of the study.
Aim 1: Determine the impact of physical activity history (group) and sex on (1a) pain processing and (1b) lifestyle behaviors in midlife adults (former athletes, master's athletes, and nonathletes).
Aim 2: Quantify the effect of physical activity history (group) and sex on the change in pain response to moderate-intensity exercise and explore differences in pain response to exercise modality (i.e., strength versus aerobic).
