Sports cardiology researchers from Texas Presbyterian Hospital recently published their new study in the journal Circulation.
They wanted to demonstrate that cardiac adaptation to regular exercise is based on the training load, not just genetics. They enrolled 12 sedentary human volunteers in a 1-year training program. All participants underwent supervised training, frequent MRI scans, and even cardiac catheterization at the beginning and end of the study.
The endurance training began with exercising 30 to 45 minutes three to four times per week by brisk walking, jogging, swimming, or cycling. Then, after a couple of months of base training, exercise intensity and duration was gradually increased. After 9 months, a long run was added to a steady dose of interval training. At the end of the study, average exercise time per week was 7 to 9 hours.
The results were striking. The right and left ventricles of all participants underwent structural changes seen in elite-level athletes. RV mass and volume increased significantly and immediately. Months later, when more intense intervals were introduced, the researchers observed the same eccentric hypertrophy in the LV. VO2max surged by an average of 20%. Cardiac compliance, diastolic volume at a given pressure, increased significantly – but nowhere near as much as elite athletes.
At the end of the study, all the previously sedentary subjects completed their endurance goals: a marathon for 10 of them, an Olympic-distance triathlon for one and a cycling “century” (100 miles) for one.
