# Effects of Controlled Supramaximal High-Intensity Interval Training on Cardiorespiratory Fitness and Global Cognitive Function in Older Adults: The Umea HIT Study-A Randomized Controlled Trial PMID: 36972981 Journal: The journals of gerontology. Series A, Biological sciences and medical sciences Published: 2023 Aug 27 Authors: Simonsson E, Levik Sandström S, Hedlund M, Holmberg H, Johansson B, Lindelöf N, Boraxbekk CJ, Rosendahl E ## Question Does watt-controlled supramaximal HIT adapted for older adults improve cardiorespiratory fitness and global cognition more than moderate-intensity training, and what are its effects on cardiovascular, muscular, cognitive, quality-of-life, adherence, and safety outcomes? ## Summary This randomized trial compared a controlled supramaximal cycling HIT protocol with moderate-intensity interval cycling in nonexercising older adults. Both groups improved VO2peak similarly and lowered blood pressure, while global cognition did not improve. HIT had advantages for working memory and knee extensor strength, used half the session time, had high attendance, and reported no serious adverse events. ## Population - Nonexercising older adults aged 66-79 years. - Sample size: 68 - Age: 66-79 years. - Sex: 44% male. - Fitness level: No regular moderate- or high-intensity exercise during the past year; baseline physical activity suggested some participants were more active than intended. - Health status: Relatively healthy older adults; excluded movement-limiting dysfunction, heart/lung symptoms with exercise, poor BP control or untreated hypertension, insulin-treated diabetes, MMSE <27, chronic/progressive neurological disease, and household sharing with another participant. ## Methodology - Randomized controlled superiority trial with parallel allocation to supramaximal HIT or MIT. - 3 months, 25 offered sessions including two introductory sessions. - Group training on indoor bicycles at a local exercise facility in Umea, Sweden, with clinical screening and blinded outcome assessment. - Randomized and controlled study design. ## Protocol - Controlled supramaximal cycling HIT. - Modality: Stationary cycling. - Work intervals: 10 x 6 seconds. - Recovery: 54 seconds between intervals: 24 seconds passive and 30 seconds active recovery. - Sets or repetitions: 10 intervals. - Intensity: Started at 60% of estimated MPO6; progressed in 4% MPO6 steps; by intervention end mean target was 428 W, 110% MPO6 and 316% MAP. - Session duration: 20 minutes. - Frequency: 2 sessions/week. - Program length: 3 months. - Progression: Escalation/de-escalation criteria based on target achievement, RPE, and participant tolerance. - Moderate-intensity interval cycling. - Modality: Stationary cycling. - Work intervals: 3 x 8 minutes. - Recovery: 3 minutes between bouts: 30 seconds passive and 150 seconds active recovery. - Sets or repetitions: 3 bouts. - Intensity: Started at 40% MAP and progressed in 4% MAP steps; by intervention end mean workload was 84 W, 69% MAP. - Session duration: 40 minutes. - Frequency: 2 sessions/week. - Program length: 3 months. - Progression: Progressed after session 3 with de-escalation for RPE >=16 or other criteria. ## Outcomes ### VO2peak Status: improved VO2peak improved significantly overall with no between-group difference between HIT and MIT. Overall mean increase 1.38 mL/kg/min, 95% CI 0.77 to 1.98; between-group difference 0.05 mL/kg/min, 95% CI -1.17 to 1.25. ### Global cognition Status: no clear change Global cognitive function did not improve and did not differ between groups. Overall change 0.02, 95% CI -0.05 to 0.09; between-group difference 0.11, 95% CI -0.03 to 0.24. ### Working memory and knee extensor strength Status: improved Working memory and maximal isometric knee extensor strength showed between-group advantages for HIT. Working memory MD 0.32, 95% CI 0.01 to 0.64; knee strength MD 0.07 N*m/kg, 95% CI 0.003 to 0.137. ### Blood pressure Status: improved Systolic and diastolic blood pressure decreased overall irrespective of group. SBP -2.09 mmHg, 95% CI -3.54 to -0.64; DBP -1.27 mmHg, 95% CI -2.31 to -0.25. ### Safety/adherence Status: mixed Attendance was high and no serious adverse events occurred, but discomfort/adverse-event reports were recorded in 9.7% of attended-session contexts when combining since-previous and current-training reports. 146 reports across 1,497 attended sessions; 52 in HIT and 94 in MIT; 70% musculoskeletal; no serious AE. ## Practical Insights - For older adults, short supramaximal intervals can be tolerable when intensity is externally controlled, supervised, and adjusted conservatively. - Do not claim global cognitive benefits; the signal was limited to working memory and should be interpreted cautiously. - Very short intervals with long recovery may reduce discomfort risk compared with longer all-out sprints. ## Limitations - Active MIT comparator reduced ability to detect between-group differences. - Some participants may have been more active than intended at baseline. - VO2peak rather than criteria-based VO2max was used. - Large interindividual variability. - Findings apply to medically screened, relatively healthy adults aged 66-79, not frailer or more diseased populations. - Exact warm-up/cooldown durations were in supplementary material rather than fully reported in main text. ## Safety And Adherence - No adverse event was considered serious. - Participants reported discomfort since prior training in 83 sessions and during current training in 63 sessions. - Most reported events were musculoskeletal pain/soreness/numbness. - Medical screening excluded several higher-risk conditions. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/36972981/) (pubmed) - [DOI](https://doi.org/10.1093/gerona/glad070) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10460559/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.