Two nights of poor sleep can impair the function of blood vessels, a study has found.
Scientists believe that over a long period, the effects of lack of sleep could contribute to heart disease.
The research was carried out on eight healthy adults aged 20 to 35 who were only allowed to sleep for four hours during each of three consecutive nights.
At the end of this time there was a significant reduction in their ability to adjust to increased blood flow. Their blood vessels failed to dilate as they should to allow more blood to pass through them.
After a third night of restricted sleep, blood vessel function returned to normal.
The researchers believe this was an adaptive response to acute loss of sleep.
Other tests showed a loss of breathing control linked to poor sleep. Exposure to moderately high levels of carbon dioxide did not produce the expected increase in the depth and rate of breathing.
The scientists suspect the findings may help explain the known association between sleep loss and heart disease.
"If acute sleep loss occurs repetitively over a long period of time, then vascular health could be compromised further and eventually mediate the development of cardiovascular disease," said lead researcher Keith Pugh, from the University of Birmingham.
Loss of breathing control could play a role in sleep apnoea, a sleep disorder in which their airways are restricted, said the scientists. Sleep apnoea has also been linked to heart disease.
The findings were presented at the Experimental Biology meeting taking place in Boston, US.