Effects of Cardiovascular Fitness and Body Composition on Maximal Core Temperature in Collegiate Football Players During Preseason.

McClelland, JM, Godek, SF, Chlad, PS, Feairheller, DL, and Morrison, KE. Effects of cardiovascular fitness and body composition on maximal core temperature in collegiate football players during preseason. J Strength Cond Res 32(6): 1662-1670, 2018-This study evaluated the effects of body mass index (BMI) and aerobic fitness (V[Combining Dot Above]O2max) on maximal core temperature values (Tcmax) in 17 National Collegiate Athletic Association Division III football players during preseason. The subjects included 9 backs (BKs) and 8 linemen (LM). V[Combining Dot Above]O2max testing was performed 1 week before preseason. Core temperature was monitored by ingestible sensor every 10 minutes during practices on day 4 (D1), day 5 (D2), day 7 (D3), and postacclimatization on day 14 (D4). Wet bulb globe temperature (WBGT) was recorded on each collection day. Independent, paired t-tests and Pearson's correlations were performed (α = 0.05). There were no significant correlations between V[Combining Dot Above]O2max and Tcmax on D1 (WBGT = 29.07° C) or D2 (WBGT = 30.93° C), but on D3 (WBGT = 31.39° C) there was a nonsignificant moderate negative correlation (r = -0.564, p = 0.090). There were no significant correlations between BMI and Tcmax on D1 or D2, but on D3 there was a nonsignificant moderate positive correlation (r = 0.596, p = 0.069). Paired t-tests revealed that overall Tcmax (D1-3) (38.56 ± 0.32° C) was statistically higher (p = 0.002) than D4 (38.16 ± 0.30° C). Independent t-tests between groups showed that the Tcmax values during preacclimatization (D1-D3) were significantly higher in LM (38.50 ± 0.37° C) than BKs (38.16 ± 0.35° C) (p = 0.007). V[Combining Dot Above]O2max was significantly lower (p = 0.006) in LM (36.89 ± 6.40 ml·kg·min) than BKs (47.44 ± 7.09 ml·kg·min), and BMI was significantly higher (p = 0.019) in LM (35.59 ± 4.00 kg·m) than BKs (28.68 ± 3.38 kg·m). The results of this study demonstrate that LM are significantly less fit than BKs and have a greater BMI. When WBGT was the highest on D3, the results suggest that those with lower V[Combining Dot Above]O2max and higher BMI experienced a higher Tcmax.

Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players.

Studies report that football players have high blood pressure (BP) and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD) and carotid artery intima-media thickness (IMT). Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 ± 0.06 mm versus 0.46 ± 0.07 mm) and larger brachial artery diameter during FMD (4.3 ± 0.5 mm versus 3.7 ± 0.6 mm), but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2 ± 6.4 mmHg versus 122.4 ± 6.8 mmHg), submaximal exercise (150.4 ± 18.8 mmHg versus 137.3 ± 9.5 mmHg), maximal exercise (211.3 ± 25.9 mmHg versus 191.4 ± 19.2 mmHg), and 24-hour BP (124.9 ± 6.3 mmHg versus 109.8 ± 3.7 mmHg). Football players also had higher fasting glucose (91.6 ± 6.5 mg/dL versus 86.6 ± 5.8 mg/dL), lower HDL (36.5 ± 11.2 mg/dL versus 47.1 ± 14.8 mg/dL), and higher body fat percentage (29.2 ± 7.9% versus 23.2 ± 7.0%). Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk.