High-Intensity Interval Training in Older Adults: a Scoping Review

High-intensity interval training (HIIT) is an increasingly popular form of aerobic exercise which includes bouts of high-intensity exercise interspersed with periods of rest. The health benefits, risks, and optimal design of HIIT are still unclear. Further, most research on HIIT has been done in young and middle-aged adults, and as such, the tolerability and effects in senior populations are less well-known. The purpose of this scoping review was to characterize HIIT research that has been done in older adults including protocols, feasibility, and safety and to identify gaps in the current knowledge. Five databases were searched with variations of the terms, "high-intensity interval training" and "older adults" for experimental or quasi-experimental studies published in or after 2009. Studies were included if they had a treatment group with a mean age of 65 years or older who did HIIT, exclusively. Of 4644 papers identified, 69 met the inclusion criteria. The average duration of training was 7.9 (7.0) weeks (mean [SD]) and protocols ranged widely. The average sample size was 47.0 (65.2) subjects (mean [SD]). Healthy populations were the most studied group (n = 30), followed by subjects with cardiovascular (n = 12) or cardiac disease (n = 9), metabolic dysfunction (n = 8), and others (n = 10). The most common primary outcomes included changes in cardiorespiratory fitness (such as VO2peak) as well as feasibility and safety of the protocols as measured by the number of participant dropouts, adverse events, and compliance rate. HIIT protocols were diverse but were generally well-tolerated and may confer many health advantages to older adults. Larger studies and more research in clinical populations most representative of older adults are needed to further evaluate the clinical effects of HIIT in these groups.

The Benefits of High-Intensity Interval Training on Cognition and Blood Pressure in Older Adults With Hypertension and Subjective Cognitive Decline: Results From the Heart & Mind Study

Background: The impact of exercise on cognition in older adults with hypertension and subjective cognitive decline (SCD) is unclear.

Objectives: We determined the influence of high-intensity interval training (HIIT) combined with mind-motor training on cognition and systolic blood pressure (BP) in older adults with hypertension and SCD.

Methods: We randomized 128 community-dwelling older adults [age mean (SD): 71.1 (6.7), 47.7% females] with history of hypertension and SCD to either HIIT or a moderate-intensity continuous training (MCT) group. Both groups received 15 min of mind-motor training followed by 45 min of either HIIT or MCT. Participants exercised in total 60 min/day, 3 days/week for 6 months. We assessed changes in global cognitive functioning (GCF), Trail-Making Test (TMT), systolic and diastolic BP, and cardiorespiratory fitness.

Results: Participants in both groups improved diastolic BP [F_{(1, 87.32)} = 4.392, p = 0.039], with greatest effect within the HIIT group [estimated mean change (95% CI): −2.64 mmHg, (−4.79 to −0.48), p = 0.017], but no between-group differences were noted (p = 0.17). Both groups also improved cardiorespiratory fitness [F_{(1, 69)} = 34.795, p < 0.001], and TMT A [F_{(1, 81.51)} = 26.871, p < 0.001] and B [F_{(1, 79.49)} = 23.107, p < 0.001]. There were, however, no within- or between-group differences in GCF and systolic BP at follow-up.

Conclusion: Despite improvements in cardiorespiratory fitness, exercise of high- or moderate-intensity, combined with mind-motor training, did not improve GCF or systolic BP in individuals with hypertension and SCD.

Clinical Trial Registration:ClinicalTrials.gov (NCT03545958).

Evaluation of the Get Active Questionnaire in community-dwelling older adults

Physical activity screening prior to starting a physical activity program is important to identify if there are any underlying health conditions. However, many older adults do not complete such assessments prior to beginning their physical activity program. This project compared the Canadian Society for Exercise Physiology's newly developed Get Active Questionnaire (GAQ) to a standardized exercise stress test in terms of screening out versus screening in false-positive GAQ tests. A convenience sample of community-dwelling adults (male n = 58, female n = 54) aged 75 ± 7 years from London, Ontario, Canada, was used. Participants completed a physical exam and physical activity screening session (i.e., stress test and GAQ) at a research laboratory that routinely conducts community-based referrals. One week after the initial visit, participants returned to the study site, completed the GAQ, and were asked questions about their perceptions of physical activity screening by a research assistant. The GAQ "screened in" participants, but it did not provide the same precision of "screening out" at-risk individuals as an exercise stress test; the GAQ reduced false-positives versus the stress test, yet there was a large proportion of high false-negative results reported. The GAQ shows promise in physical activity screening in older adults to engage in exercise safely. However, the lack of precision in physical-activity screening out of at-risk populations requires further evaluation. Questionnaires such as the GAQ should be evaluated in a larger study population at various time points to further assess the validity and reliability of physical activity screening tools.

Perceptions of exercise screening among older adults

Prephysical activity screening is important for older adults' participating in physical activity. Unfortunately, many older adults face barriers to exercise participation and thus, may not complete proper physical activity screening. The purpose of this project was to conduct a thematic analysis of perceptions and experiences of community-dwelling older adults regarding prephysical activity screening (i.e., Get Active Questionnaire (GAQ) and a standardized exercise stress test). A convenience sample of adults (male n = 58, female n = 54) aged 75 ± 7 years living in the City of London, Ontario, Canada, was used. Participants completed a treadmill stress test and the GAQ at a research laboratory for community-based referrals. One week later, participants completed the GAQ again and were asked questions by a research assistant about their perceptions of the screening process. Thematic analysis of the responses was conducted. The results indicated that older adults view physical activity screening as acceptable, but not always necessary. Also, the experiences expressed by this sample of older adults indicated that physical activity screening can contribute to continued confidence (through reassurance) and can contribute to increased motivation (through yearly fitness results) in exercise participation. In conclusion, older adults may perceive screening as supportive in exercise adoption, if screening is simple, convenient, and supports older adults' motivation and confidence to exercise.