11/01/2026
Cortisol and heart rate variability (HRV) are tightly linked through the autonomic nervous system and together reflect how well the body is balancing stress and recovery. Cortisol is the body’s primary stress hormone, responsible for mobilising energy and maintaining alertness, while HRV represents the nervous system’s ability to shift between “fight-or-flight” and “rest-and-repair” states. In modern life, ongoing day-to-day pressures from work, training demands, poor sleep, mental load, and constant stimulation can keep cortisol chronically elevated. This suppresses parasympathetic activity, leading to reduced HRV, impaired recovery, disrupted sleep, lower testosterone, and increased anxiety. Practices such as contrast therapy — alternating heat and cold exposure — alongside breathwork, sleep optimisation, and parasympathetic-focused recovery techniques, stimulate vagal tone, enhance nervous system flexibility, and promote faster cortisol clearance. The result is higher HRV, improved hormonal balance, deeper recovery, and greater resilience to both physical and psychological stress.
