Combining cardio and weights lowered deaths by 60% in coronary heart disease trials

Cardiac rehabilitation has a default shape, and it is a treadmill. Someone survives a heart attack, gets referred, and spends twelve weeks walking on a moving belt while a nurse watches a monitor. Weights were historically kept out of it, on the reasonable-sounding worry that straining against a load spikes blood pressure in exactly the person who can least afford it.

That caution has been softening for years without much data behind the softening. Gois and colleagues, writing in Sports Medicine - Open, note that until now there were little data concerning the effects of combined training on the exercise capacity, muscle strength, health-related quality of life, and mortality of coronary heart disease patients.

Pooling the randomized trials that did exist, they found the combination reduced mortality compared to non-exercising usual care. Deaths ran at about two fifths the rate.

The number that gets used to predict survival

Coronary artery disease, also called coronary heart disease, is the most common type of heart disease, and the best predictor of how someone with it will fare is not a scan or a cholesterol panel. It is how much oxygen they can use at full effort.

Combined training improved relative peak VO2 of 2.20 ml/kg/min against non-exercising usual care. Peak oxygen uptake is measured in milliliters of oxygen per kilogram of body weight per minute, and a gain of a little over two is roughly the difference between struggling on a flight of stairs and managing it without stopping. In this population each unit gained has been repeatedly tied to lower risk of dying.

Strength moved too, and by more than the fitness numbers suggest. Peak torque rose 16.69 N.m and handgrip strength 4.68 kgf against usual care, which are large changes in muscle that had been quietly wasting since the cardiac event.

Against the treadmill, not just against nothing

Beating usual care is the easy comparison. Almost any supervised program beats being sent home with a leaflet, and a result that only clears that bar says little about what a rehab service should actually run.

The harder test was against aerobic training alone, the current default, and the combination won there as well. It improved peak oxygen uptake by 0.28, six-minute walking distance by 21.98 meters, one-repetition maximum by 0.61 kg, peak torque by 4.03 N.m, and quality of life by 0.50 compared to aerobic training.

Twenty-two meters on a six-minute walk is the one to hold onto. It is a small distance and a well-studied outcome, and in heart failure and coronary disease populations a change of that size sits near the threshold where patients report noticing a difference in daily life.

Against resistance training alone, the combination improved relative peak oxygen uptake by 1.91 ml/kg/min. So each half of the combination adds something the other cannot: the weights add strength the treadmill does not build, and the treadmill adds the aerobic capacity the weights do not.

What to make of a 60% reduction in deaths

A 60% lower death rate is the headline and the number that deserves the most caution.

Deaths are rare events in rehabilitation trials, which run for months rather than decades and enrol hundreds rather than thousands. A pooled mortality estimate built from few events moves a long way on a small number of cases, and its true range is wide even when the central figure looks dramatic.

What makes the direction credible is not the mortality figure on its own. It is that fitness, strength and quality of life all moved the same way in the same trials, and that peak oxygen uptake is itself one of the strongest known predictors of survival in this population. A treatment that raises the predictor and lowers the outcome is telling a consistent story.

Why lifting was kept out for so long

The original objection was mechanical. Lifting a heavy weight produces a sharp, brief rise in blood pressure, and a heart with narrowed arteries is a heart you do not want to load suddenly.

What changed the thinking is that supervised resistance work in rehabilitation is not heavy lifting. It is moderate loads, controlled tempo, and full breathing rather than the breath-holding strain that produces the spike. Under those conditions the pressure response is modest and the muscle response is not.

The muscle side of the argument has also grown more urgent. People survive cardiac events at older ages than they used to, and arrive at rehabilitation with the sarcopenia that comes with age plus the deconditioning that comes with weeks of illness. Aerobic training does very little about either.

What a patient should ask for

Nobody should add weights to their own cardiac rehabilitation on the strength of a meta-analysis. What is safe depends on the event, on how well the heart is pumping, and on what medication is doing to heart rate and blood pressure, none of which a pooled estimate knows.

What this evidence supports is a specific question to a rehabilitation team: is there a resistance component in this program, and if not, why not? That is a different conversation from asking whether exercise is allowed.

Physical activity contributes to the prevention and management of noncommunicable diseases such as cardiovascular diseases, cancer and diabetes, and the general recommendation is at least 150 minutes of moderate-intensity physical activity per week. What this analysis adds is that for a heart patient, how those minutes are spent appears to matter as much as how many there are.