By: Sarah Schmermund, M.A.
We’ve said it before, and we’ll say it again.? If you can carry on a conversation, it doesn’t count as cardio.
Thankfully, research is finally backing us up.
For years, the “Talk Test” has served as the marker for a workout’s intensity.? If you can speak aloud while exercising, you are working hard enough to improve your health and fitness.? This test was based on the knowledge that the ideal intensity to gain benefits from exercise is moderate, requiring about 70 to 85 percent of your maximum heart rate.? Historically, researchers have found that, talking fairly easily while exercising is an accurate way to determine you’re working at a moderate intensity, thus providing you the most benefits.? But more recent research incorporating the consideration of the lactate threshold says this isn’t always the case.
The lactate threshold is your body’s limit for processing lactic acid – a cellular fuel released in your muscles.? Lactic acid is partly related to post-workout muscle soreness, and for this reason it used to be thought of as a toxin that contributed to muscle fatigue.? Moderate-to-high intensity exercise causes the production of lactic acid to increase, at times to a point exceeding your body’s ability to clear it from your muscles, thus reaching your lactate threshold – the point at which the muscles tend to give out (and you couldn’t possibly complete another rep).? Research (and your trainer) has shown that, in order to exceed your current fitness level and increase your strength and speed, some workouts must include an intensity difficult enough that it hits just below your lactate threshold.? You have to work the muscles until they can barely work anymore; lactic acid aids in the degrading and rebuilding of our muscles so they can get stronger.
In a recent experiment at the University of New Hampshire, participants were asked to recite the Pledge of Allegiance aloud while jogging on a treadmill at an increasingly brisk pace.? At three minute intervals, the participant would again recite the pledge and tell the researcher whether speaking now was easy, difficult, or close to impossible (often just a loud gasp).? Throughout the session, the researchers tracked the participant’s heart rate and lactate threshold, among other measures of exertion (ie: oxygen-carrying capacity).
The researchers found that those participants who were already fit begin to find talking “close to impossible” only as they reach their lactate threshold.? At 70 to 85 percent their maximum heart rate, the recommended for moderate workout intensity, fit individuals were able to recite the pledge without much difficulty.? Thus, the ability to talk while exercising (the golden rule of the Talk Test), was not providing these fit individuals with a workout adequate or strenuous enough to increase their fitness level.
So which rule is right?? It turns out, both.? A review of the past research reveals that the Talk Test was established with participant pools that were generally unfit or sedentary.? Because these individuals tend to have higher heart rates even when not exercising, they appear to be adequately exerting themselves within the moderate intensity range when talking is moderately difficult (but still possible).
So, unless you’re new to exercise (and thus the Talk Test/30 minutes of moderate-intensity exercise recommendation still applies), ?the rule remains to be: exert yourself at an intensity that produces the feeling that you just couldn’t possibly do another rep or go any faster (or recite the Pledge of Allegiance).? If you can carry on a conversation, it doesn’t count as cardio.