title: Physical Activity: Absolute Intensity versus Relative-to-Fitness-Level Volumes.
abstract: This study aimed 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.
  
  
  
  A total of 23,224 Finnish employees (10,201 men and 13,023 women; ages 18-65 yr; body mass index = 18.5-40.0 kg·m) participated in heart rate recording for 2+ d. 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 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.
  
  
  
  According to absolute intensity categorization, the volume of both moderate- and vigorous-intensity PA was higher in men compared with women (P < 0.001), in younger compared with older participants (P < 0.001), and in normal weight compared with overweight or obese participants (P < 0.001). When the volume of PA intensity was estimated relative to individual fitness level, the differences were much smaller. Mean daily minutes of absolute vigorous-intensity PA were higher than those of relative intensity minutes in normal weight men ages 18-40 yr (17.7, 95% confidence interval [CI] = 16.9-18.6, vs 8.6, 95% CI = 8.0-9.1; P < 0.001), but the reverse was the case for obese women ages 41-65 yr (0.3, 95% CI = 0.2-0.4, vs 7.8, 95% CI = 7.2-8.4; P < 0.001).
  
  
  
  Compared with low-fit persons, high-fit persons more frequently reach an absolute target PA intensity, but reaching the target is more similar for relative intensity.
authors.affiliation: 1Department of Health Sciences, University of Jyväskylä, Jyväskylä, FINLAND; 2Department of Signal Processing, Tampere University of Technology, Tampere, FINLAND; and 3Department of Psychology, University of Jyväskylä, Jyväskylä, FINLAND.
authors.forename: Urho M
authors.initials: UM
authors.lastname: Kujala
authors.forename: Julia
authors.initials: J
authors.lastname: Pietilä
authors.forename: Tero
authors.initials: T
authors.lastname: Myllymäki
authors.forename: Sara
authors.initials: S
authors.lastname: Mutikainen
authors.forename: Tiina
authors.initials: T
authors.lastname: Föhr
authors.forename: Ilkka
authors.initials: I
authors.lastname: Korhonen
authors.forename: Elina
authors.initials: E
authors.lastname: Helander
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015716:Electrocardiography, Ambulatory; D015444:Exercise / Q000502:physiology*; D005260:Female; D005387:Finland; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology; D050177:Overweight / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D056152:Respiratory Rate / Q000502:physiology; D012737:Sex Factors; D055815:Young Adult