A new study published in Scientific Reports reveals that long-term endurance training not only benefitscardiovascular healthand muscle strength but also significantly enhances immune function in older adults. The study found that older individuals with a long history of enduranceexercisehad more adaptable and metabolically efficient immune cells, specifically natural killer (NK) cells, compared to their sedentary peers. NK cells are a type of white blood cell essential for early immune defense, responsible for eliminating infected and abnormal cells. The researchers studied nine participants with an average age of 64, divided into trained and untrained groups. Those with over 20 years of endurance training showed NK cells that were less inflammatory, more energy-efficient, and more resilient to immune challenges. To understand how exercise impacts immune function, the team also tested NK cell responses to inflammatory triggers and pharmacological agents such as propranolol and rapamycin. Despite the inhibition of key immune signaling pathways, NK cells from trained individuals maintained function, while those from untrained individuals showed cellular exhaustion. "Decades of physical activity seem to 'train' the immune system to avoid exaggerated inflammatory responses," said Dr. Luciele Minuzzi of Justus Liebig University Giessen. These findings support the role of exercise in healthy aging, offering critical insight into preventing inflammation-related diseases through long-term physical activity. Reference:Luciele Guerra Minuzzi, Helena Batatinha, Christopher Weyh, Vidya Srokshna Balasubramanian Lakshmi, Carmen Fiuza-Luces, Beatriz G. Gálvez, Alejandro Lucia, Ana Maria Teixeira, Natascha Sommer, José Cesar Rosa-Neto, Fabio Santos Lira, Karsten Krüger. Natural killer cells from endurance-trained older adults show improved functional and metabolic responses to adrenergic blockade and mTOR inhibition. Scientific Reports, 2025; 15 (1) DOI: 10.1038/s41598-025-06057-y