Is high-intensity interval training safe after 60?

High-intensity interval training looks safe for healthy older adults in small, supervised trials, with no serious problems reported. Too few trials tracked harms to rule out rare ones.

Who it's for

Healthy adults over 60, ideally with a gradual start and guidance.

What to expect

Fitness gains similar to or a bit better than steady moderate exercise.

Watch out for

Rare heart events or injuries could be missed; individual check-ups matter.

What guidelines say

A 2019 clinical guideline says safety worries remain a common barrier to interval training. It sets out step-by-step methods to set heart rate targets and monitor people with heart and metabolic conditions4Guideline · 2019Guidelines for the delivery and monitoring of high intensity interval training in clinical populations.The framework involves an individualized step-by-step process to calculate, validate, and calibrate HR target zones for HIIT training to allow for appropriate workload prescription and progression. We strongly recommend this framework be used in future clinical trials investigating HIIT.Prog Cardiovasc Dis. A 2025 international consensus on exercise for older adults stresses personalized exercise plans because people respond differently1Guideline · 2025Global consensus on optimal exercise recommendations for enhancing healthy longevity in older adults (ICFSR).Particular attention is paid to the need for personalized medicine as it applies to exercise and geroscience, given the inter-individual variability in adaptation to exercise demonstrated in older adult cohorts. Overall, this consensus provides a foundation for applying and extending the current knowledge base of…J Nutr Health Aging.

What the studies show

• A trial of 51 healthy, inactive adults (average age 65) compared 8 weeks of supervised interval training, steady moderate training and no exercise. Interval training caused no adverse events and raised fitness by 11%7Randomized trial · 2016 · 18 peopleNovel all-extremity high-intensity interval training improves aerobic fitness, cardiac function and insulin resistance in healthy older adults.In conclusion, all-extremity HIIT is feasible and safe in older adults. HIIT, but not MICT, improved aerobic fitness, ejection fraction, and insulin resistance.Exp Gerontol. It was small and short, so rare harms could be missed.
• A review that pooled 29 trials in 1,227 adults aged 60 and older found interval and moderate training gave similar gains in most fitness and health measures. In higher-quality trials, interval training raised fitness more3Meta-analysis · 2024 · 1,227 peopleEffects of high-intensity interval and continuous moderate aerobic training on fitness and health markers of older adults: A systematic review and meta-analysis.HIIT and MICT produced similar changes in most of the investigated variables. In trials with greater quality (controlled vs. non-controlled trials), cardiorespiratory gains were higher in HIIT vs. MICT. These findings suggest that HIIT might be suitable for improving fitness and health in older adults.Arch Gerontol Geriatr. Safety was not its main focus.
• A review of five small studies, at high risk of bias, concluded that older adults can do interval training, with caution, individual tailoring and gradual increases in intensity5Systematic review · 2024Effects of High-Intensity Interval Training on Muscle Strength for the Prevention and Treatment of Sarcopenia in Older Adults: A Systematic Review of the Literature.HIIT training shows improvements in body composition and functional and cardiorespiratory capacity, has benefits on muscle strength, increases muscle quality and architecture, and is associated with muscle hypertrophy in healthy older adults. Nonetheless, given the shortcomings affecting primary research in terms of…J Clin Med.
• A trial of 82 people at least 6 months after a stroke (average age 65) found no adverse events over 12 weeks of interval training. Fitness rose more than with moderate exercise, but the gap was gone 8 weeks later10Randomized trial · 2024 · 2,417 peopleCardiorespiratory Fitness Benefits of High-Intensity Interval Training After Stroke: A Randomized Controlled Trial.Short-interval HIIT may be an effective alternative to MICT for improving V̇O2peak at 12 weeks postintervention.Stroke.
• An overview of 150 Cochrane reviews of exercise in all ages found minimal or no safety concerns. Serious side effects were reported in 13% of the reviews, and deaths were mostly not linked to exercise6Meta-analysis · 2020 · 32,984 peopleExercise/physical activity and health outcomes: an overview of Cochrane systematic reviews.There is a plethora of CSRs evaluating the effectiveness of physical activity/exercise. The evidence suggests that physical activity/exercise reduces mortality rates and improves QOL with minimal or no safety concerns.BMC Public Health. This covers exercise generally, not interval training.
• In a trial of 1,635 older adults with mobility limits, a moderate-intensity program had serious adverse events in 49.4% versus 45.7% with health education. The difference was small and could be down to chance9Randomized trial · 2014 · 1,635 peopleEffect of structured physical activity on prevention of major mobility disability in older adults: the LIFE study randomized clinical trial.A structured, moderate-intensity physical activity program compared with a health education program reduced major mobility disability over 2.6 years among older adults at risk for disability. These findings suggest mobility benefit from such a program in vulnerable older adults.JAMA. These figures compare groups, so the effect for one person depends on their starting risk.

Key studies

Safety

Interval training means short bursts of hard effort, so people with heart disease, past stroke or heart failure need individual assessment and monitoring4Guideline · 2019Guidelines for the delivery and monitoring of high intensity interval training in clinical populations.The framework involves an individualized step-by-step process to calculate, validate, and calibrate HR target zones for HIIT training to allow for appropriate workload prescription and progression. We strongly recommend this framework be used in future clinical trials investigating HIIT.Prog Cardiovasc Dis. Guidance advises gradual progression and consulting a health professional first5Systematic review · 2024Effects of High-Intensity Interval Training on Muscle Strength for the Prevention and Treatment of Sarcopenia in Older Adults: A Systematic Review of the Literature.HIIT training shows improvements in body composition and functional and cardiorespiratory capacity, has benefits on muscle strength, increases muscle quality and architecture, and is associated with muscle hypertrophy in healthy older adults. Nonetheless, given the shortcomings affecting primary research in terms of…J Clin Med. Trials in heart failure used moderate aerobic exercise, not interval training, and found other adverse events similar to usual care8Randomized trial · 2009 · 796 peopleEfficacy and safety of exercise training in patients with chronic heart failure: HF-ACTION randomized controlled trial.In the protocol-specified primary analysis, exercise training resulted in nonsignificant reductions in the primary end point of all-cause mortality or hospitalization and in key secondary clinical end points. After adjustment for highly prognostic predictors of the primary end point, exercise training was associated…JAMA.

What we don't know

• How often injuries or heart events happen with interval training in people over 60, since most trials are small and short.
• Whether results hold for people over 75 or with several health conditions, and for unsupervised training.