Effects of repeated exposure to acceleration forces (+Gz) and anti-G manoeuvres on cardiac dimensions and performance.

Exposure to acceleration forces (+Gz) and anti-G protective manoeuvres causes changes in cardiac preload and afterload. These changes can result in cardiac hypertrophy or enlargement. Previous studies regarding the effect of acceleration in high-G aviators (HGAs) are few and inconclusive. An echocardiographic study was initiated to determine whether there are structural or functional cardiac differences between HGAs and low-G aviators (LGAs).The present study was a cross-sectional study in which echocardiographic parameters in HGAs were compared with those in LGAs. Both retrospective and prospective data were collected. Fifty aviators were included in each group. The aviators who participated in the present study were randomly chosen from a cohort with similar demographic characteristics and flying hours. No major differences were found in cardiac dimensions and function between HGAs and LGAs. The authors speculate that the reason why no major differences were found was due to the short period of total exposure to very high +Gz forces and anti-G measures.