Exercise-induced hypoalgesia (EIH) refers to the reduction in pain sensitivity following acute exercise. Although aerobic exercise has been shown to induce hypoalgesia in healthy individuals, it remains unclear whether the magnitude of this response differs between men and women. This quasi-experimental study aims to evaluate sex differences in pressure pain thresholds following a standardized aerobic exercise protocol using a lower-limb cycle ergometer. Pressure pain thresholds will be assessed before exercise, immediately after exercise, and 30 minutes after exercise in healthy adults aged 18 to 65 years. The findings of this study may contribute to improving individualized exercise prescription strategies based on sex differences in pain modulation.
Exercise-induced hypoalgesia (EIH) is characterized by a transient reduction in pain sensitivity following acute physical exercise, measurable through pressure pain thresholds (PPTs). Aerobic exercise has been consistently shown to increase PPTs in healthy individuals through activation of endogenous pain inhibitory mechanisms, including opioid and non-opioid pathways. However, the influence of biological sex on EIH remains unclear, and understanding potential differences between men and women could have important implications for exercise prescription in clinical and healthy populations. This quasi-experimental study will include healthy male and female participants aged 18-65 years. Participants will undergo a single session of aerobic exercise on a lower-limb cycle ergometer at 70% heart rate reserve for 30 minutes. Pressure pain thresholds will be assessed using a validated digital pressure algometer at: * Quadriceps muscle (local site) * Lateral epicondyle region (remote site) Measurements will be performed at three time points: * Pre-exercise * Immediately post-exercise * 30 minutes post-exercise The primary analysis will compare changes in pressure pain thresholds between men and women using ANCOVA models adjusting for baseline values.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
30
Participants will perform a 30-minute aerobic exercise protocol using a lower-limb cycle ergometer at 70% heart rate reserve. The protocol includes: * 5-minute warm-up * 20-minute exercise at target intensity * 5-minute cool-down Heart rate will be monitored continuously using a validated heart rate monitor.
Centro Superior de Estudios Universitarios La Salle
Madrid, Madrid, Spain
Pressure Pain Threshold at Quadriceps
Pressure pain threshold measured using a digital pressure algometer at the quadriceps muscle.
Time frame: Pre-exercise, immediately post-exercise, and 30 minutes post-exercise
Pressure Pain Threshold at Lateral Epicondyle
Pressure pain threshold measured at a remote anatomical site using pressure algometry.
Time frame: Pre-exercise, immediately post-exercise, and 30 minutes post-exercise
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