Muscle size alone does not equal strength, says Brazil. Bodybuilders may have visually larger muscles than marathon runners or professional basketball players, but few would call Arnold Schwarzenegger (circa 1970) a stronger athlete—or more fit—than LeBron James. In Brazil’s words, “You can modify a car with all the fancy accessories and paint jobs you want. But if it doesn’t have an engine, it isn’t going anywhere.”
This is where stamina, or the ability to exert oneself at the same intensity for an extended time, comes into play. But it’s not just good for the clock and the scoreboard. According to the experts, increased stamina is also key to improving the funtion of your heart and lungs. And the name of the game is diversification.
“The best way to increase stamina is to vary your intensities,” says Guida. One way to do this is to switch between the four different levels of training: long-duration steady (for example, running at a moderate six miles per hour for an hour); interval training (shifting between that moderate six and a more intense eight miles per hour); high-intensity interval training (toggling between a full sprint and six miles per hour); and lactate threshold training (going almost full throttle for a consistent 15 to 20 minutes).
While switching up your patterns of physical intensity, don’t just stick to your comfort activity, Guida warns. “Throw in some different modes of exercise. So if I’m a runner, I should also try some biking, some agility training, or resistance training. Combining the different ways to exercise also helps you handle stamina better.”
To increase stamina, Laura encourages clients to pace their breathing when doing cardio, and steers them away from running while their heart rate is an issue. “I find biking, elliptical, and swimming are great ways to increase stamina that don’t put too much stress on the body,” she says.