The More You Resist, the More It Costs

Your body is designed to adapt. When you exercise, your heart beats faster. When you need to act, your muscles tense. When something feels threatening or important, your attention sharpens. Hormones are released, energy is mobilized, and multiple systems adjust to help you meet what is happening.

This ability to maintain stability by continuously adjusting to changing circumstances is called allostasis (McEwen, 1998). It is not a flaw. It is essential.

The difficulty begins when the body has to keep adapting without enough opportunity to recover. That is where allostatic load enters the picture.

How your body keeps you steady

Allostasis is the body's ongoing work of staying regulated in a changing environment. Heart rate, blood pressure, metabolism, immune activity, and stress hormones can all shift to match demand (McEwen & Stellar, 1993).

In an ideal cycle, activation rises when something requires a response, then eases when the moment passes. Problems tend to appear when that cycle is interrupted, when demands stack up, recovery is short, or the body never quite returns to baseline.

When the load adds up

Imagine holding a bag of apples. For a few minutes it feels easy. After an hour your forearm is tense and your shoulder compensates. After several hours the same weight hurts, not because the apples got heavier, but because the cost of carrying them accumulated over time.

Physiology works in a similar way. Ongoing accumulation has a cost. When challenges repeat, overlap, or rarely resolve, the body may mobilize the same resources again and again (McEwen, 1998).

Over time, those cumulative consequences are called allostatic load (McEwen & Stellar, 1993). The phrase is sometimes described as physiological "wear and tear," though that metaphor should not be taken too literally. Allostatic load is not a single substance building up inside you.

Four body systems under strain

When stress stays on and recovery stays off, damage is rarely confined to one organ. Research on allostatic load tracks how the wear spreads (Juster, McEwen, & Lupien, 2010). In plain terms, four linked systems are often affected:

1. Cardiovascular system

Chronic stress keeps SAM and HPA axis activity high, sustaining adrenaline, noradrenaline, and cortisol (McEwen, 1998). The heart pumps harder while vessels stay constricted, which over time can harm vessel linings and contribute to persistent hypertension and atherosclerosis (Juster, McEwen, & Lupien, 2010).

2. Brain and nervous system

The brain directs the stress response and is also altered by it. Long-running cortisol exposure can reduce growth and connectivity in the hippocampus and prefrontal cortex while increasing amygdala reactivity, affecting memory, planning, and emotional tone (McEwen, 2007).

3. Metabolic and endocrine systems

Short-term stress mobilizes fuel; chronic load can leave glucose and lipids chronically elevated (McEwen, 2003). That pattern is linked to visceral fat, insulin resistance, and metabolic syndrome (Juster, McEwen, & Lupien, 2010).

4. Immune and inflammatory systems

Cortisol briefly suppresses inflammation; with chronic overexposure, immune cells can become less responsive to those signals (McEwen, 1998). The system may shift toward low-grade inflammation, with markers such as IL-6, TNF-α, and CRP staying high (Juster, McEwen, & Lupien, 2010).

These are population-level patterns (Ma et al., 2022), not a map of what will happen to you personally.

The body is one coordinated system, not a set of separate parts.

Recovery is part of resilience

We often treat resilience as the ability to withstand more. Biologically, resilience is also about how effectively you can recover.

Holding the bag for ten minutes is different from holding it for six hours straight. The weight is the same; the cost is not. Putting it down, resting, and picking it up later is not weakness. It is how load stays manageable.

Sleep, rest, movement, social connection, emotional regulation, and periods when demands are reduced all give physiological systems a chance to move back toward baseline. Without that, the body may remain in repeated or prolonged activation.

We are meant to move between states

Allostasis does not aim for permanent calm. A completely unchanging physiological state would be incompatible with everyday life. We need activation, challenge, movement, and periods of intense focus, and we need rest.

The goal is not zero stress. The goal is the ability to move between states: activation when something requires action, recovery when the demand has passed, activation again when the next challenge arrives.

Difficulty often shows up when those transitions get harder, or when activation greatly outweighs recovery.

Sometimes the problem isn't the size of the challenge. It is the duration.

Sometimes it is not how intensely you respond, but how often you have to respond. And sometimes it is not that you cannot carry the load. It is that you have forgotten you are allowed to put it down.

The body is extraordinarily capable of adaptation. Adaptation was never meant to be an endless state of resistance.

References

• Juster, R.-P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers of chronic stress and impact on health and cognition. Neuroscience & Biobehavioral Reviews, 35(1), 2–16. (doi.org)
• Ma, H., et al. (2022). Allostatic load and mortality: A systematic review and meta-analysis. American Journal of Preventive Medicine, 63(1), 131–140. (doi.org)
• McEwen, B. S. (1998). Protective and damaging effects of stress mediators. New England Journal of Medicine, 338(3), 171–179. (doi.org)
• McEwen, B. S. (1998). Stress, adaptation, and disease: Allostasis and allostatic load. Annals of the New York Academy of Sciences, 840(1), 33–44. (doi.org)
• McEwen, B. S. (2003). Interacting mediators of allostasis and allostatic load: Towards a better understanding of the physiological basis of chronic disease. Metabolism, 52(10 Suppl 2), 15–16. (doi.org)
• McEwen, B. S. (2007). Physiology and neurobiology of stress and adaptation: Central role of the brain. Physiological Reviews, 87(3), 873–904. (doi.org)
• McEwen, B. S., & Stellar, E. (1993). Stress and the individual: Mechanisms leading to disease. Archives of Internal Medicine, 153(18), 2093–2101.