TUTCRIS

PURPOSE: To investigate in a real-life setting how moderate and vigorous intensity physical activity (PA) volumes differ according to absolute intensity recommendation and relative to individual fitness level by sex, age, and body mass index (BMI).

METHODS: 23 224 Finnish employees (10 201 men, 13 023 women; ages 18-65 years; BMI 18.5-40.0 kg/m) participated in heart rate recording for 2+ days. We used heart rate and its variability, respiration rate, and on/off response information from R-R interval data calibrated by participant characteristics to objectively determine daily PA volume, as follows: daily minutes of absolute moderate (3-<6 multiples of resting metabolic rate; METs) and vigorous (≥6 METs) PA; and minutes relative to individual aerobic fitness for moderate (40-<60% of oxygen uptake reserve) and vigorous (≥60%) PA.

RESULTS: According to absolute intensity categorization, the volume of both moderate and vigorous PA was higher in men compared to women (P < .001), in younger compared to older participants (P < .001), and in normal weight compared to overweight or obese participants (P < .001). When the volume of PA intensity was estimated relative to individual fitness level, the differences were much smaller. Mean daily minutes of absolute intensity vigorous PA were higher than those of relative intensity minutes in normal weight men ages 18-40 years (17.7, 95% CI 16.9-18.6 vs. 8.6, 95% CI 8.0-9.1; P < .001), but the reverse was the case for obese women ages 41-65 years (0.3, 95% CI 0.2-0.4 vs. 7.8, 95% CI 7.2-8.4; P < .001).

CONCLUSION: Compared to low fit persons, high fit persons more frequently reach an absolute target PA intensity, but reaching the target is more similar for relative intensity.