Which of the following is a chronic adaptation to regular training?

• A. Increased resting heart rate
• B. Capillarisation is increased
• C. Decreased stroke volume
• D. Decreased VO2 max

Answer: (B)

Regular endurance training produces long-term changes that boost the body’s ability to deliver and use oxygen. Increasing capillarisation means more capillaries form around muscle fibres, raising capillary density. This shortens the diffusion distance for oxygen into the muscle and helps remove carbon dioxide and other wastes more efficiently, allowing neurons and mitochondria to work at higher intensities for longer. Because these structural changes take weeks to months of consistent training and persist with ongoing activity, they’re considered chronic adaptations. In contrast, resting heart rate tends to decrease with training, stroke volume generally increases, and VO2 max increases rather than decreases, so those options don’t describe a chronic adaptation.