Saliva Test Measures Exercise Intensity

Making News:

Looking for an accurate way to gauge a client’s work effort? Just ask the client to spit. A study published in the March issue of Journal of Sports Science & Medicine (2004; 3 [1], 8–15) shows that cortisol levels in saliva after a workout can indicate whether the exercise session was high or low intensity.

Cortisol is a steroid hormone made in the adrenal glands. Sometimes called “the stress hormone,” it regulates blood pressure and cardiovascular function as well as the body’s use of proteins, carbohydrates and fats. Cortisol secretion increases in response to any stress in the body, including exercise.

Eight men and nine women took part in the study, completing two resistance training trials. The high-intensity training consisted of six 10-repetition sets using 75 % of 1-repetition maximum on a Smith machine squat and bench press exercise (12 sets total). The low-intensity protocol included three 10-repetition sets at 30% of 1-repetition maximum.

Researchers took saliva samples before and after each exercise session and again 30 minutes later. Immediately after the high-intensity session, cortisol levels were 97% higher than they were before the session. There was no significant change after low-intensity exercise. Between the low- and high-intensity protocols, the difference in salivary cortisol levels immediately postworkout was 145%.