Introduction: Human morphology and physiology are not designed inherently to function in microgravity. Hence, exposure to hypo or microgravity, as it occurs during space exploration, poses challenges in the form of peculiar adaptive physiological processes in healthy astronauts. These changes may vary (to a certain extent) depending on type of physical fitness (namely, aerobic or anaerobic) and may have definitive impact on short duration space mission. The study aimed to examine the cardiovascular dynamics during short duration exposure to simulated microgravity condition in differently trained individuals. Material and Methods: Temporal variations in body fluid distribution were studied during 6° head-down tilt (HDT) for 4-hours in 31 healthy males in age range of 20–40 years divided into three groups based on their physical training, namely; resistance trained (RT), endurance trained (ET), and untrained (UT). This was based on their history of physical training, VO2 max, and peak anaerobic power. Results: Heart rate in the ET group and RT group showed increasing and decreasing trend respectively, however, statistically remained non-significant. Systolic and diastolic pressures showed a significant increase in the ET group at the 4th h of HDT as compared to baseline and the 1st h. No significant variation in pulse pressure could be seen. Mean arterial pressures showed significant increase in the ET group at the 4th h of HDT as compared to baseline and the 1st h of HDT. Stroke volume and cardiac output did not vary significantly. Conclusion: ET individuals in the present study demonstrated decreased sensitivity of baroreceptors than RT or UT individuals, whereas, the RT group demonstrated more stability/resilience in terms of cardiovascular dynamics than ET and UT groups under exposure to short duration simulated microgravity.

Introduction: A number of studies on military and civil parachuting injuries have been published in the past. Most of the studies place the incidence of parachuting injuries to vary between 0.22% and 0.89%. The profile of injuries sustained during jumps by Indian paratroopers from Paratrooper Training School (PTS), Agra, between 2013 and 2019 was analyzed. Material and Methods: A retrospective analysis of Indian military parachuting injuries was done to assess injury patterns from the records of static line and combat free fall jumps, available at the PTS. The data pertaining to 270 injuries sustained from 256 jumps were analyzed in terms of number of jumps by each paratrooper, type of course/ mission, age, time of the of jump (day/ night), type of parachute used, wind speed at the time of drop, terrain on which the paratrooper landed, the location / part of body injured, the diagnosis, and finally the possible modality of injury using descriptive statistics. Results: The incidence of injuries ascertained from the records varied from 0.054% to 0.10% with a mean incidence of 0.083% from 306,986 jumps recorded over 7 years. Most injuries were related to refresher jumps and static line jumps. There were three fatalities recorded in this period, all due to failure of main and standby parachutes. Most of the injuries were sustained at the time of landing (218, 86.17%). Lower limb injuries accounted for maximum injuries (109, 40.37%), followed by truncal injuries 95 (35.19%) and upper limb injuries 33 (12.22%). Conclusion: The study brings out an interesting aspect of significantly less military parachuting injuries seen in the present study vis-à-vis reported in literature. A high degree of physical fitness and rigorous training are probably responsible for this low incidence. Increasing the duration of refresher training and physical conditioning may further reduce the occurrence of injuries. A cost-efficacy analysis of the same may be done before effecting changes in the training programme.