title: Affective Responses to Repeated Sessions of High-Intensity Interval Training.
abstract: OBJECTIVE
  Vigorous exercise feels unpleasant, and negative emotions may discourage adherence to regular exercise. We quantified the subjective affective responses to short-term high-intensity interval training (HIT) in comparison with moderate-intensity continuous training (MIT).
  
  
  METHODS
  Twenty-six healthy middle-age (mean age, 47 ± 5 yr; mean VO2peak, 34.2 ± 4.1 mL·kg⁻¹·min⁻¹) sedentary men were randomized into HIT (n = 13, 4-6 × 30 s of all-out cycling efforts at approximately 180% of peak workload with 4-min recovery) or MIT (n = 13, 40- to 60-min continuous cycling at 60% of peak workload) groups, performing six sessions within two weeks. Perceived exertion, stress, and affective state were recorded before, during, and after each session.
  
  
  RESULTS
  Perceived exertion and arousal were higher, and affective state, more negative during the HIT than that during MIT sessions (P < 0.001). HIT versus MIT exercise acutely increased the experience of stress, tension, and irritation and decreased positive affect (P < 0.05). In addition, satisfaction was lower and pain and negative affect were higher in the HIT than those in the MIT group (P < 0.05). However, perceived exertion and displeasure experienced during exercise alleviated similarly in response to HIT and MIT over the 6 d of training. Peak oxygen consumption increased (P < 0.001) after intervention (HIT, 34.7 ± 3.9 vs 36.7 ± 4.5; MIT, 33.9 ± 4.6 vs 35.0 ± 4.6) and was not different between HIT and MIT (P = 0.28 for group × training).
  
  
  CONCLUSIONS
  Short-term HIT and MIT are equally effective in improving aerobic fitness, but HIT increases experience of negative emotions and exertion in sedentary middle-age men. This may limit the adherence to this time-effective training mode, even though displeasure lessens over time and suggests similar mental adaptations to both MIT and HIT.
authors.affiliation: 1Turku PET Centre, University of Turku and Turku University Hospital, Turku, FINLAND; 2Department of Biomedical Engineering and Computational Science and Brain Research Unit, O.V. Lounasmaa Laboratory, Aalto University, Espoo, FINLAND; and 3Department of Biostatistics, University of Turku, Turku, FINLAND.
authors.forename: Tiina
authors.initials: T
authors.lastname: Saanijoki
authors.forename: Lauri
authors.initials: L
authors.lastname: Nummenmaa
authors.forename: Jari-Joonas
authors.initials: JJ
authors.lastname: Eskelinen
authors.forename: Anna M
authors.initials: AM
authors.lastname: Savolainen
authors.forename: Tero
authors.initials: T
authors.lastname: Vahlberg
authors.forename: Kari K
authors.initials: KK
authors.lastname: Kalliokoski
authors.forename: Jarna C
authors.initials: JC
authors.lastname: Hannukainen
mesh_terms: D000328:Adult; D000339:Affect; D015444:Exercise / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010465:Perception / Q000502:physiology; D010806:Physical Education and Training / Q000379:methods*; D005082:Physical Exertion; D013315:Stress, Psychological