Saliva secretion is regulated by the autonomic nervous system. Parasympathic stimuli increase the secretion
of water and mucin MUC5B, whereas sympathetic stimuli such as physical exercise increase the secretion of amylase and other
proteins. In the present study we investigated the effect of physical exercise, as a sympathetic stimulus, on salivary flow
rate and output of MUC5B, amylase, lysozyme and total protein.
Unstimulated whole saliva was collected
before exercise (1), after 10 min exercise with moderate intensity by running with a heart rate around 130 beats per minute
(2), followed by 10 min exercise with high intensity by running to exhaustion (3) and after 30 min recovery (4). Salivary
flow rate, protein and MUC5B concentration, and amylase and lysozyme activity were determined. Saliva protein composition
was analysed using SDS-PAGE and immunoblotting.
Salivary flow rate, protein and lysozyme secretion increased
after exercise with moderate intensity and increased further after exercise with high intensity (p < 0.01). Amylase and
MUC5B increased after exercise with moderate intensity (p < 0.0001), but did not differ significantly between moderate
and high exercise intensity. SDS-PAGE analysis and immunoblotting showed that, especially after exercise with high intensity,
the concentrations of several other salivary proteins, including MUC7, albumin, and extra-parotid glycoprotein, also increased.
may not only lead to the anticipated increase in amylase and protein secretion, but also to an increase in salivary flow rate
and MUC5B secretion.