# Effects of Exercise Duration and Intensity on Maximal Exercise Capacity Over 6 Months in Coronary Heart Disease and Type 2 Diabetes—A Secondary Analysis of the LeIKDTrial

## TL;DR

This study finds that longer exercise duration improves maximal exercise capacity in older patients with heart disease and diabetes, while intensity has a smaller effect when adherence is high.

## Contribution

The study identifies the specific impact of exercise duration and intensity on maximal oxygen uptake in older patients with coronary heart disease and type 2 diabetes.

## Key findings

- Exercise duration significantly increases peak oxygen uptake (V̇O2peak) in patients with CHD and T2DM.
- Higher exercise intensity is associated with increased V̇O2peak only in patients with high adherence.
- Training duration in the first two weeks predicts long-term adherence to exercise.

## Abstract

Exercise training is recommended in coronary heart disease (CHD) and type 2 diabetes (T2DM) patients alike; however, uncertainty remains on the influence of exercise intensity and duration in older patients with both entities. To address this, we performed a secondary analysis including 201 patients (67.9 ± 8.2 years; 84.1% men) from the LeIKD trial (NCT038359), which introduced 6 months of home‐based telemedicine‐supported exercise intervention in patients with CHD and T2DM. We assessed the relationships between exercise duration and intensity with change in peak oxygen uptake (V̇O2peak) (simple and multiple regression analyses, α = 0.05). V̇O2peak increased by 0.42 mL/kg/min per hour of endurance exercise/week (95% CI: 0.17–0.66, p = 0.001). Exercise intensity was not significantly associated with the change in V̇O2peak (p = 0.10). In a subgroup of patients with high adherence (≥ 66.7% of prescribed total duration and meeting prescribed exercise duration in ≥ 50% of weeks of intervention), a 10% increase in exercise intensity (mean % heart rate reserve (HRR)) was associated with an increase in V̇O2peak of 0.26 mL/kg/min (95% CI: 0.00–0.52; p = 0.05). Longer training duration within the initial 2 weeks of intervention was significantly associated with high adherence over 6 months (increased likelihood per 10 min/week: OR of 1.09 [95% CI: 1.05–1.14], p < 0.001). Therefore, exercise duration but not intensity influences changes in V̇O2peak during exercise intervention in a high‐risk population of older patients with CHD and T2DM. In patients with high adherence to exercise duration, higher exercise intensity led to an additional increase in V̇O2peak. Training duration within the first 2 weeks was an important predictor of long‐term adherence.

Trial Registration:
https://www.clinicaltrials.gov: Identifier: NCT038359