Saliva is a biological fluid rich in information about individual health. Everyone produces between 0.5 and 1ml per minute, and it contains valuable information about levels of minerals, stress hormones and immunoglobulins (involved in immune responses and allergies).
Now a team of sports scientists at Massey University in New Zealand has investigated how exercise affects the makeup of saliva. Curiously, during a one-hour spin session, the rate of saliva production didn’t change in men. For women, however, there were a number of changes. This reflects the metabolic and hormonal differences experienced in women and men during sustained physical activity.
Because women tend to be lighter (and smaller), they experience greater dehydration, reflected in rising levels of electrolytes in their saliva. This dehydration is one factor that triggers a greater stress hormone response, which in turn was measured in a steady increase in the level of the stress hormone cortisol.
The researchers have identified a useful way to gather key information about the health and fatigue of athletes. The differences also point to the importance of sustained hydration during cycling, particularly for women.
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