[Prediction of the degree of nocturnal oxygen desaturation in sleep apnea syndrome by estimating the testosterone level]

We studied the influence of hypoxia due to sleep apnea on testosterone (T) secretion. It was conducted on the basis of an idea that sustained hypoxia may depress T secretion. The subjects consisted of 15 male patients with no drug administration whose complaints were snoring and/or obesity. The subjects participated in a sleep study on two consecutive nights. During the first night we collected blood samples starting every 4 hours from 10 PM via a catheter and measured T. From the data of the second night, we calculated total desaturation time with more than 4% from the baseline SaO2. According to the amount of this desaturation time, the subjects were divided into 2 groups; desaturation time less than 80 min in group 1 and longer in group 2, respectively. The peak value was seen at 6 AM in group 1 and at 10 AM in group 2. We investigated the correlation between the ratio of T10/T6, which is the ratio of T level at 10 AM to that at 6 AM, and parameters of sleep disorders related to oxygen desaturation. Total 4% desaturation time in total sleep period and non REM period significantly correlated with this ratio. From the diagram illustrating the correlation between the ratio and total 4% desaturation time in total sleep period, we could assume that if the ratio is beyond 1, the subject may have had more than about 80 min of total 4% desaturation time.