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The effects of alterations in mean skin temperature (Tsk) on intravascular volume and protein responses to 90 min of bicycle ergometer exercise have been studied in six male subjects. The onset of exercise was accompanied by an initial rapid haemoconcentration, followed by a slower, progressive haemoconcentration as core and skin temperatures increased. Cooling the skin after 30 min of exercise abolished the slow haemoconcentration, and thereafter, even when Tsk was raised to the pre-exercise level during the final 30 min of exercise, little further change in blood volume was observed. During skin warming, and during recovery from exercise, there was an increase in the total intravascular protein content compared with before exercise. It is concluded that the progressive haemoconcentration often described during cycling exercise may be attributed to an increase in skin blood flow occurring as a result of rises in core and skin temperature, the associated increase in filtration through the cutaneous capillaries causing a progressive loss of plasma volume. The mechanism of the augmentation of intravascular protein remains unclear.

Nine male subjects took part in a comparative evaluation of four indirect tests commonly used for predicting maximum aerobic power (VO2 max). In three of these tests (involving cycling, stepping and walking) VO2 max was predicted from submaximal heart rates; in the fourth, VO2 max was predicted from the time taken to run 2 km. Additionally, VO2 max was predicted from the body fat content. All predicted values were compared with the VO2 max determined directly on a treadmill. The best estimates of VO2 max were provided by the timed run, and by the step test. Both heart rate measured during walking and body fat content proved totally inadequate for the reliable prediction of VO2 max. Taking into account such factors as cost, safety, and the time required for testing, it is concluded that the timed run is the submaximal test most suited to the indirect determination of VO2 max.

Effect of diazepam on sleep in man was investigated in a series of placebo controlled studies and the data on various measures from two groups (young adults and middle age) were retrospectively analysed. Variability of the measures between the two groups with placebo was not different, but the variability of their response to the drug was different, and that of the middle aged group was high. In the young adults there were drug effects, but in the middle aged group no drug effects could be established. The studies suggest that variability of data must be taken into consideration when it is used to indicate the most appropriate dose range. If the variability of response is low the data may indicate the likely effect of the drug on each individual. On the other hand if the variability is high then data obtained from analysis of the group may have limited relevance, and suggest doses which are too high for the majority of the individuals within that group.

Forty-seven cases of osteoblastic skeletal metastases were examined, of which 26 were from primary carcinoma of the breast. In two of these cases the metastases were of an unusual semicircular configuration. In each case the patient survived for at least four years after the discovery of metastases. This appearance may represent a better form of host response to metastatic disease.

Maximal aerobic power (VO2 max) was determined by direct measurement in 10 male subjects whilst exercising on a bicycle ergometer, and whilst running uphill on a treadmill at speeds of 10 and 12 km/h. There was no significant difference between VO2 max measured at the two treadmill speeds, but the VO2 max measured on the bicycle was 20% lower than on the treadmill. An estimate of the variance of the treadmill determined VO2 max was obtained from repeated measurements on five subjects. The 95% tolerance interval about a single measurement of VO2 max was +/- 7.8 ml.kg-1.min-11. It is recommended that when indirect methods for determining VO2 max are calibrated against the direct method, the latter should be based upon the treadmill. Reservations are expressed concerning the value of the direct method for determining VO2 max, and of the concept of VO2 max as a measure of physical fitness.