Correlates of maximal oxygen consumption during treadmill exercise

According to the Balke treadmill protocol, 39 healthy male USAF volunteers were subjected to maximal exercise. The subjects as a group passed the anaerobic threshold by the end of exercise since average venous lactate concentrations increased from 11.2 +/- 1.6 mg% (95% confidence limits) to 93.0 +/- 8.5 mg% (95% confidence limits), and the average gas exchange ratio (R) at the end of the exercise was greater than unity (p less than 0.0005). Tests for correlations showed weak but statistically significant (p less than 0.05) relationships between change in venous lactic acid concentrations and R (r = 0.44) and maximal heart rate (r = 0.34). Maximal oxygen consumption was correlated with time of exercise (r = 0.70) and subject weight (r = 0.33). Subject age and initial plasma lactate concentrations were not significantly correlated with any other variables. Multiple linear regression yielded an equation for prediction of maximal oxygen consumption which included terms for time of exercise and subject weight. Although the multiple correlation coefficent (r = 0.75) was statistically significant (p less than 0.05), it was considered insufficient for accurate prediction of maximal oxygen consumption.     

Marginal neutrophil pool size in normal subjects and neutropenic patients as measured by epinephrine infusion

The marginal granulocyte pool (MGP) was measured by epinephrine infusion in normal and neutropenic subjects. Neutrophil response curves to doses of 0.025 to 0.3 mg. in three normal subjects indicated that maximal neutrophil response was achieved by 0.1 mg. In 21 normal subjects, absolute neutrophils increased from 700 to 3,100 per microliter. The percentage increase ranged from 18 to 107 per cent of baseline. The per cent increase tended to be greater with low-normal baseline neutrophils than with high-normal neutrophils, although this relationship was not observed when increase was determined in absolute values. In neutropenic patients mean per cent increase of neutrophils was greater than observed in normal subjects, 121 vs. 50 per cent. Although the increase expressed in absolute neutrophil numbers was less in subjects with lower baseline neutrophil concentrations, there was an inverse correlation between the baseline neutrophil concentrations, there was an inverse correlation between the baseline neutrophils and the per cent increment following epinephrine. Mean increase was 200 per cent in patients with less than 200 neutrophils per microliter, compared with 61 per cent in patients with 1,000 to 1,500 neutrophils per microliter. These results indicate that circulating granulocyte pool (CGP) size may be misleading with respect to total blood neutrophils and in a sense confirm the concept of shift neutropenia, a decreased CGP and MGP as neutropenia becomes more profound suggests that shift neutropenia may be a normal physiologic methanism rather than a distinct neutropenic syndrome.     

Effects of school-based aerobic exercise on blood pressure in adolescent girls at risk for hypertension

OBJECTIVE: The purpose of this study was to investigate 1. the extent of weight gain by high school wrestlers between an evening weigh-in and the first round of wrestling the next morning and 2. the relationship between weight gain and wrestling success. METHODS: Body weights of competitors (N = 260) in a high school wrestling tournament were recorded at official weigh-in and again, about 12 h later, immediately before the first round of wrestling. Data for the heavyweight class was excluded. Weight gain (WG in kg), relative weight gain (RWG in %), and weight discrepancy between opponents (WD in kg) were calculated from data obtained at the weighings. The mean WG for all wrestlers was 1.3 kg +/- 1.1 with a range of -2.0 kg to +4.4 kg. This corresponds to RWG of 2.2 +/- 1.7% body weight. RESULTS: WG in the lower weight classes was statistically larger than that seen in the highest weight classes (P < 0.05). The smallest RWG was seen in the 189-lb. class (1.1 +/- 1.9%), and the largest RWG was seen in the 112-lb. class (3.0 +/- 2.1%). Average WD between competitors was 1.7 +/- 1.5 kg (range 0-7.5 kg.). Average WD was largest in the two heaviest classes. Average WG was 1.5 +/- 1.1 kg for winners and 1.2 +/- 1.0 kg for losers. RWG was 2.4 +/- 1.8% for winners and 1.9 +/- 1.6% for losers. CONCLUSIONS: The difference in WG and RWG between winners and losers was significant (P < 0.05). In 74 of the 130 bouts (57%), the heavier wrestler was successful (NS).