The effect of aerobic exercise on tumour blood delivery: a systematic review and meta-analysis.

PURPOSE: Tumour blood vessels are structurally and functionally abnormal, resulting in areas of hypoxia and heterogeneous blood supply. Aerobic exercise may modulate tumour blood flow and normalise the tumour microenvironment to improve chemotherapy delivery. This systematic review and meta-analysis aimed to evaluate the effect of the aerobic exercise mode on tumour hypoxia, vascularisation and blood flow. METHODS: Four online databases were searched. Preclinical and clinical randomised controlled trials examining the effects of aerobic exercise training on hypoxia, vascularisation or blood flow in solid tumours were included. The risk of bias was assessed and a meta-analysis performed. RESULTS: Seventeen preclinical studies and one clinical study met criteria. Eleven studies assessed hypoxia, 15 studies assessed vascularisation and seven evaluated blood flow. There was large variability in measurement methods, tumour types and exercise program designs. The overall risk of bias was unclear in clinical and preclinical studies, owing to poor reporting. There was no significant effect of aerobic exercise on hypoxia (SMD = -0.17; 95% CI = -0.62, 0.28; I2 = 60%), vascularisation (SMD = 0.07; 95% CI = -0.40, 0.55; I2 = 71%) or blood flow (SMD = 0.01; 95% CI = -0.59, 0.61; I2 = 63%). CONCLUSION: There is heterogeneity in methodology, resulting in evidence that is inconsistent and inconclusive for the effects of aerobic exercise on hypoxia, vascularisation and blood flow. Most evidence of aerobic exercise effects on tumour blood flow is in animal models, with very limited evidence in humans.

Vaccination reaction rate is unaltered by ambient temperature on the day.

Minor reactions are often experienced following the human papillomavirus (HPV) vaccination and negative vaccination experiences may discourage individuals from seeking future vaccinations. Ambient temperature is suggested to be linked to reaction rates. Optimising immunisation programs requires understanding associations of temperature and reactions. To investigate a potential association between temperature and reactions, logistic regressions were performed on data obtained for a two-year period from a vaccine safety monitoring system for children (ages 10-15 years) who received the HPV vaccination (n = 20466) and from publicly available meteorological records in Australia. Reaction rate was 8.3% overall and higher with concomitant vaccination versus HPV alone (9.3% vs 7.8%, p=<0.001). Logistic regression found no relationship between reactions and maximal temperature on the day of vaccination (p = 0.581); controlling for concomitant vaccination, age and gender did not alter the temperature-reaction relationship (p = 0.851) but did identify concomitant vaccination as a significant predictor. Our results suggest immunisation programs must weigh the advantages of improved vaccination coverage resulting from concomitant vaccination against an increase in reaction rates and, importantly, can be safely administered across a range of temperatures.