Do gym users have lower hospitalization rates compared to non-gym users, particularly in terms of cardiovascular disease, hypertension, and diabetes?

Gym Users Have Lower Hospitalization Rates Compared to Non-Gym Users

Regular gym participation and structured exercise training are associated with reduced hospitalization rates, particularly for cardiovascular disease, with the magnitude of benefit directly proportional to exercise volume and fitness level achieved.

Evidence for Reduced Hospitalization Rates

Heart Failure Populations

• Exercise training reduces heart failure hospitalizations by approximately 28% when combined with mortality as a composite endpoint 1
• In the HF-ACTION trial involving 2,331 heart failure patients, exercise training showed an 11% reduction in all-cause mortality or hospitalization (hazard ratio 0.89,95% CI 0.81-0.99) after adjustment for prognostic factors 1
• Meta-analyses demonstrate that cardiac rehabilitation likely reduces both all-cause and heart failure-specific hospitalizations, though primary analyses of individual trials showed mixed results 1

General Cardiovascular Disease

• Patients achieving peak VO₂ >22 mL/kg/min (high fitness, typical of regular gym users) demonstrate 61% reduction in cardiac deaths and 55% reduction in all-cause deaths compared to those with <15 mL/kg/min 2, 3
• Moderate fitness levels (15-22 mL/kg/min, achievable with consistent gym attendance) result in 34% reduction in cardiac deaths and 34% reduction in all-cause deaths 3
• Exercise volume >6 MET-hours per week produces 26% reduction in all-cause death or hospitalization, compared to 18% reduction with >4 MET-hours per week 2

Older Adult Populations

• Among adults aged 78-85 years, physically active individuals had significantly lower emergency room usage (15.8% vs 37.4% at age 78; 30.6% vs 50.8% at age 85) and hospitalization rates (10.5% vs 16.7% at age 78; 22.1% vs 37.8% at age 85) compared to inactive peers 4
• Initiating physical activity even after age 78 resulted in similar hospitalization benefits as those who were consistently active (OR 1.20 for hospitalization, 95% CI 0.48-3.02), while stopping activity increased hospitalization risk (OR 1.85,95% CI 1.06-3.23) 4

Specific Disease Populations

• In a South African health insurer study of 948,974 members, hospitalization costs and admission rates were progressively lower with increasing gym visit frequency: low active (4-23 visits/year), moderate active (24-48 visits/year), and high active (>48 visits/year) groups all showed reduced costs compared to inactive members (<3 visits/year) 5
• For COVID-19, performing at least 150 minutes/week of moderate-intensity or 75 minutes/week of vigorous-intensity physical activity was associated with 34.3% reduction in hospitalization prevalence (PR = 0.657, p = 0.046) after adjustment for age, sex, BMI, and preexisting diseases 6

Mechanisms Underlying Hospitalization Reduction

Cardiovascular Benefits

• Exercise training improves endothelial function, reduces catecholamine spillover, increases peripheral oxygen extraction, and improves peak oxygen consumption 1
• Reduced myocardial oxygen demand at any given workload through lower heart rate, systolic blood pressure, and circulating catecholamines allows greater work capacity before ischemia 2
• Enhanced fibrinolysis, improved endothelial function, and decreased sympathetic tone contribute to cardiovascular protection 3

Metabolic Improvements

• Structured exercise interventions of at least 8 weeks lower A1C by an average of 0.66% even without significant BMI change in diabetic patients 3
• Exercise reduces progression to diabetes by 58% through lifestyle modification 2
• Physical activity attenuates central cardiometabolic risk factors including blood pressure, triglycerides, and fasting glucose 2

Critical Fitness Thresholds for Hospitalization Reduction

Minimum Effective Dose

• At least 150 minutes per week of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity activity represents the minimum effective dose 1, 2, 3
• This translates to approximately 24-48 gym visits per year (moderate active category) to begin seeing hospitalization benefits 5
• Even 1.5 hours per week of moderate-to-vigorous activity produces 20% mortality reduction, representing the largest marginal benefit for previously sedentary individuals 2, 7

Optimal Targets

• Peak VO₂ >22 mL/kg/min (achievable with >48 gym visits/year or high-intensity training) provides maximum protection with hazard ratios of 0.39 for cardiac deaths and 0.45 for all-cause deaths 2, 3
• Exercise volume >6 MET-hours per week optimizes the 26% reduction in death/hospitalization composite endpoint 2, 7
• For heart failure patients specifically, 95 minutes per week during months 4-6 of training showed benefits, though adherence declined to 74 minutes in later months 1

Important Caveats and Limitations

Adherence Challenges

• Decreased adherence to exercise protocols over time represents a major limitation across all exercise trials 1
• In HF-ACTION, training duration decreased from 95 minutes/week (months 4-6) to 74 minutes/week in the final study months, potentially attenuating long-term benefits 1
• Hospitalization itself increases sedentary time by 8 minutes/day for 1-3 cumulative hospital days and 16 minutes/day for ≥4 cumulative hospital days, with no evidence of recovery to pre-hospitalization activity levels 8

Population-Specific Considerations

• In the EJECTION-HF trial, there was no difference in 1-year mortality or readmission between supervised center-based exercise and home exercise programs (60% vs 65%), though a trend toward benefit existed in participants under 70 years (OR 0.56,95% CI 0.30-1.02) 1
• The primary analyses of major trials (HF-ACTION, EJECTION-HF) did not show statistically significant benefits on clinical events without adjustment for prognostic factors 1
• Benefits appear strongest when exercise is supervised, particularly in diabetic populations where supervised training exhibits greater compliance and blood glucose control 3

Dose-Response Relationship

• A linear dose-response relationship exists between physical activity and health effects, at least up to a point, supporting recommendations for the most sedentary populations 9
• The relationship between fitness and mortality follows a dose-response pattern where higher fitness levels confer progressively greater survival benefits 2
• Total energy expenditure matters more than the specific type of physical activity performed (sports, planned exercise, household work, or occupational tasks all provide comparable benefits when energy expenditure is constant) 9

Clinical Implementation Strategy

Risk Stratification

• Measure baseline fitness via exercise tolerance test to determine MET capacity or peak VO₂ 2, 7
• Categorize patients: low fitness (<15 mL/kg/min or ≤5 METs), moderate fitness (15-22 mL/kg/min or 5.1-7.0 METs), or high fitness (>22 mL/kg/min or >9 METs) 2, 3, 7

Prescription Algorithm

• For low fitness patients (≤5 METs): Begin with 75-150 minutes/week of moderate-intensity activity, targeting 5.1-7.0 METs within 3-6 months 7
• For moderate fitness patients (5.1-9 METs): Prescribe 150-300 minutes/week moderate-intensity or 75-150 minutes/week vigorous-intensity activity, progressing toward >6 MET-hours/week 2, 7
• For high fitness patients (>9 METs): Maintain ≥300 minutes/week moderate-intensity or ≥150 minutes/week vigorous-intensity activity, adding muscle-strengthening exercises on ≥2 non-consecutive days per week 7

Special Populations

• Heart failure patients: Recommend cardiac rehabilitation programs including supervised aerobic exercise training for 36 sessions over 30 months, with heart rate reserve targets to guide intensity 1
• Diabetic patients: Prescribe combined aerobic and resistance training (twice as effective as either alone), with no more than 2 consecutive days without activity since insulin resistance returns within 48-72 hours 3
• Older adults (≥60 years): Emphasize that initiating activity even in the eighth decade provides similar hospitalization benefits as lifelong activity, with the highest fitness level associated with 41% lower all-cause mortality 2, 4