Net heart rate to prescribe physical activity in middle-aged to older active adults

This study had a twofold purpose: i) to develop a regressionequation to estimate metabolic equivalent (met) in walk/run byheart rate increment above rest (nethr), and; ii) to determinenethr thresholds for light, moderate, and vigorous physicalactivity (pa), from middle aged to elderly. sample 1 (predictionsample) comprised 39 subjects (19 male and 20 female), with58.2 ± 11.0 years old. sample 2 (validation sample) comprised40 subjects (18 male and 22 female) with 63.3 ± 7.0 years old.each participant did the following activities in sequence, a15min rest period in supine position, walk at 3km/h, walk at4.5km/h, and walk at 6km/h, for 6 min at each walk velocityinterval. the oxygen up-take (vo2) and heart rate (hr) werecontinuously and simultaneously assessed. a hierarchical linearmodel was used to analyze the relationship between metabolicequivalent (met) and nethr. the regression equation for metprediction was: met = 1.265780 + 0.109479 nethr. thenethr thresholds (upper limit) for light, moderate and vigorouspa were 16 and 35 and 70 bpm, respectively. nethr is apractical, valid and non-invasive method to prescribe physicalactivity, taking in account individual characteristics (hr at restcombined with nethr) in middle-aged to older adults.