Hyderabad: A new study by the National Institute of Nutrition (NIN), Hyderabad, has found that years of athletic training bring significant changes to the human body, affecting metabolism, blood characteristics and even the gut microbiome. It revealed that these changes vary depending on the type of sport pursued.The study, published in the international journal ‘Frontiers in Nutrition’, found that endurance and strength athletes develop distinct physiological and microbial adaptations over years of structured training. The findings, researchers said, could pave the way for more personalised nutrition plans, training methods and recovery strategies to improve athletic performance while supporting long-term health.Researchers compared three groups — elite endurance athletes such as marathon runners, cyclists and swimmers; elite strength athletes, including weightlifters; and physically less active men — to understand how different training styles influence the body. The study involved 80 healthy men aged between 18 and 35 years from sports academies and training centres in Hyderabad. Of these, 27 were endurance athletes, 29 were strength athletes, and 24 were sedentary participants. All athletes had undergone at least five consecutive years of structured training, trained for a minimum of eight hours a week and had competed at state or national level during the previous year.The researchers used advanced scientific techniques, including Dual-energy X-ray Absorptiometry (DXA) to assess body composition, indirect calorimetry to measure resting metabolic rate, dietary assessments, blood investigations and quantitative PCR-based gut microbiome analysis to build comprehensive physiological profiles of the participants.The study found clear differences between the two groups of athletes. Endurance athletes were leaner, burned more fat at rest and showed blood characteristics associated with improved oxygen transport — adaptations that help sustain prolonged aerobic activity. Strength athletes, on the other hand, had greater skeletal muscle mass, higher bone mineral density and elevated resting metabolic rates, reflecting the demands of resistance-based training and power sports.Researchers also found that athletic training influenced the composition of gut bacteria. Compared with sedentary participants, elite athletes had higher levels of bacteria linked to protein and fat metabolism. Sedentary individuals showed relatively higher levels of Lactobacillus. Differences were also observed between endurance and strength athletes, suggesting that long-term training and dietary habits shape the gut microbiome in sport-specific ways.Dr K Venkatesh, scientist E at ICMR-NIN, who led the research, said the findings demonstrate how sustained physical activity simultaneously affects multiple physiological systems, including body composition, metabolism, bone health and the gut microbiome, highlighting the wide-ranging health benefits of regular exercise.ICMR-NIN director Dr Bharati Kulkarni said the study underlines the need for personalised nutrition and training strategies tailored to the specific physiological demands of different sports. Such an approach, she said, could help athletes improve performance, recover faster, reduce injury risk and maintain better long-term health.
