Something shifts when you hit your forties. The easy miles feel a little harder, recovery takes longer, and niggles that once disappeared overnight now linger. But here's the truth: masters runners often run their best times well into their forties and beyond. The key is training smarter, not giving up.

What Actually Changes After 40

Understanding the physiological changes helps you adapt effectively rather than fight against biology.

VO2 max decline—Aerobic capacity decreases by roughly 10% per decade after 30, though trained runners lose it more slowly ^[1]. This is partly due to reduced maximum heart rate and changes in muscle composition.

Slower recovery—The inflammatory response to exercise becomes more prolonged with age. What once required 24 hours of recovery may now need 48–72 hours ^[2].

Muscle loss—Sarcopenia (age-related muscle loss) begins in your thirties and accelerates without intervention. Runners can lose 3–8% of muscle mass per decade if they don't actively maintain it ^[3].

Hormonal shifts—Testosterone and oestrogen decline affects muscle protein synthesis, bone density, and recovery capacity in both men and women ^[4].

Connective tissue changes—Tendons and ligaments become less elastic and slower to repair, increasing injury risk ^[5].

None of this means you should stop running. It means you need to adapt your approach.

Recovery Becomes Non-Negotiable

In your twenties, you could stack hard sessions and survive on enthusiasm. After 40, recovery is where adaptation happens—skip it and you'll break down rather than build up.

Practical recovery strategies:

• Space hard efforts—Allow at least 48 hours between quality sessions. Many masters runners thrive on a hard-easy-easy pattern rather than hard-easy.
• Prioritise sleep—Growth hormone release during deep sleep becomes even more critical for tissue repair. Aim for 7–9 hours consistently ^[6].
• Manage inflammation wisely—Chronic low-grade inflammation increases with age and impairs recovery. Curcumin has been shown to modulate inflammatory responses and support recovery from exercise-induced muscle damage ^[7].
• Don't skip easy days—Easy means genuinely easy. Your ego might resist, but keeping recovery runs truly gentle is essential.

RunStrong includes Curcumin C3 Complex® with BioPerine® to support the body's inflammatory response—particularly valuable when recovery naturally takes longer.

Strength Training: No Longer Optional

If you're not lifting weights after 40, you're leaving performance and injury resilience on the table. Strength training directly counters sarcopenia, maintains bone density, and protects joints ^[8].

Key principles for runners over 40:

• Compound movements—Squats, deadlifts, lunges, and step-ups build functional strength that translates to running.
• Progressive overload—Gradually increase resistance over time. Light weights with endless repetitions won't provide sufficient stimulus.
• Consistency over intensity—Two quality sessions per week beats sporadic heavy lifting. Recovery matters here too.
• Single-leg work—Running is essentially a series of single-leg hops. Bulgarian split squats and single-leg Romanian deadlifts build stability and address imbalances.

Research shows that masters athletes who combine endurance training with resistance work maintain more muscle mass and better running economy than those who only run ^[9].

Protecting Your Bones and Joints

Running is weight-bearing and generally good for bones, but the equation shifts with age. Bone remodelling slows, and the risk of stress fractures increases—particularly if vitamin D levels are inadequate ^[10].

Vitamin D plays a critical role in calcium absorption and bone mineralisation. Deficiency is common in UK adults, especially during winter months when sunlight exposure is insufficient ^[11]. For runners over 40, ensuring adequate vitamin D status is essential for maintaining bone health and reducing fracture risk.

Joint health also deserves attention. The cartilage in your knees, hips, and ankles has been absorbing impact for decades. While running doesn't cause arthritis in healthy joints, existing wear can become symptomatic ^[12]. Managing inflammation through nutrition and appropriate training loads helps keep joints comfortable.

RunStrong provides vegan Vitamin D3 at 10 mcg (400 IU) per serving, supporting bone health year-round.

Energy Systems and Fat Metabolism

Metabolic efficiency often improves with years of training. Experienced runners are typically better at using fat for fuel, sparing glycogen for harder efforts. This is an advantage worth nurturing.

L-Carnitine plays a key role in transporting fatty acids into the mitochondria for oxidation. Research suggests supplementation can enhance fat metabolism during exercise, supporting endurance performance ^[13]. For masters runners building aerobic base, optimising fat oxidation helps maintain energy across longer training sessions.

Carbohydrate needs don't disappear—you still need glycogen for quality sessions and races. But the ability to run easy and moderate efforts primarily on fat is a genuine asset.

Iron: Often Overlooked in Masters Runners

Iron deficiency doesn't discriminate by age. The combination of foot-strike haemolysis (destruction of red blood cells from repeated impact), sweat losses, and potential GI microbleeding means runners of all ages are at elevated risk ^[14].

Symptoms of low iron can mimic overtraining or simply 'getting older'—fatigue, reduced performance, heavy legs. If you're struggling with unexplained tiredness, it's worth checking your ferritin levels.

RunStrong includes Iron Bisglycinate, a highly bioavailable form that's gentle on the stomach—helping maintain iron status without the gastrointestinal issues associated with other forms.

Adjusting Your Training Structure

The fundamental principles of training don't change after 40, but the application needs tweaking:

1. Reduce volume, maintain intensity
   You may not handle the same weekly mileage, but you can maintain fitness with slightly less volume if quality sessions are preserved. A smaller dose of intensity provides sufficient stimulus when recovery time is optimised ^[15].
2. Periodise more deliberately
   Build in recovery weeks every 3–4 weeks rather than grinding through continuous training blocks. Your body needs planned downtime.
3. Listen to warning signs
   That twinge that would resolve overnight in your thirties might become an injury if ignored in your forties. Early intervention saves weeks of lost training.
4. Be flexible with the plan
   If you're excessively fatigued, adjust. Skipping or modifying one session is better than pushing through and missing two weeks.
5. Race less frequently
   Racing takes a greater toll as you age. Choose your events strategically rather than racing every weekend.

The Mental Advantage

Here's what younger runners don't have: decades of experience. You know your body, you understand pacing, and you've developed mental resilience through years of training and racing.

Masters runners often race smarter—more even pacing, better tactical awareness, less panic when things get hard. Experience is a genuine competitive advantage that partially offsets physiological decline.

Accept that personal bests may become age-graded personal bests. Shift your focus to competing well within your age group, enjoying the process, and appreciating that you're still running when many of your peers have stopped.

Final Take-Home Points

• ⏱️ Recovery is everything—Space hard sessions further apart and prioritise sleep. Your body adapts during rest, not during training.
• 💪 Strength train consistently—Two sessions per week protects against muscle loss and injury.
• 🦴 Support your bones—Ensure adequate vitamin D and calcium. RunStrong provides 10 mcg vegan D3 per serving.
• 🔥 Manage inflammation—Curcumin supports recovery when your body's inflammatory response naturally takes longer to resolve.
• 🩸 Monitor iron status—Fatigue isn't just 'getting older'. Check ferritin if performance declines unexpectedly.
• 🧠 Use your experience—Decades of running knowledge is a genuine advantage. Train smarter, not just harder.

References

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2. Fell J, Williams D. (2008). The effect of aging on skeletal-muscle recovery from exercise. Journal of Aging and Physical Activity. doi.org/10.1123/japa.16.1.97
3. Lexell J. (1995). Human aging, muscle mass, and fiber type composition. Journals of Gerontology. doi.org/10.1093/gerona/50a.special_issue.11
4. Kraemer WJ, Ratamess NA. (2005). Hormonal responses and adaptations to resistance exercise and training. Sports Medicine. doi.org/10.2165/00007256-200535040-00004
5. Magnusson SP et al. (2008). Human tendon behaviour and adaptation, in vivo. Journal of Physiology. doi.org/10.1113/jphysiol.2007.139105
6. Dattilo M et al. (2011). Sleep and muscle recovery: endocrinological and molecular basis for a new hypothesis. Medical Hypotheses. doi.org/10.1016/j.mehy.2011.04.017
7. Hewlings SJ, Kalman DS. (2017). Curcumin: A review of its effects on human health. Foods. doi.org/10.3390/foods6100092
8. Westcott WL. (2012). Resistance training is medicine: effects of strength training on health. Current Sports Medicine Reports. doi.org/10.1249/JSR.0b013e31825dabb8
9. Blagrove RC et al. (2018). Effects of strength training on the physiological determinants of middle- and long-distance running performance. Sports Medicine. doi.org/10.1007/s40279-017-0835-7
10. Lappe J et al. (2008). Calcium and vitamin D supplementation decreases incidence of stress fractures in female navy recruits. Journal of Bone and Mineral Research. doi.org/10.1359/jbmr.080102
11. Webb AR et al. (2018). Colour counts: sunlight and skin type as drivers of vitamin D deficiency at UK latitudes. Nutrients. doi.org/10.3390/nu10040457
12. Lo GH et al. (2018). Running does not increase symptoms or structural progression in people with knee osteoarthritis. Clinical Rheumatology. doi.org/10.1007/s10067-018-4121-3
13. Wall BT et al. (2011). Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise. Journal of Physiology. doi.org/10.1113/jphysiol.2010.201343
14. Telford RD et al. (2003). Footstrike is the major cause of hemolysis during running. Journal of Applied Physiology. doi.org/10.1152/japplphysiol.00631.2001
15. Tanaka H, Seals DR. (2003). Dynamic exercise performance in Masters athletes: insight into the effects of primary human aging on physiological functional capacity. Journal of Applied Physiology. doi.org/10.1152/japplphysiol.00320.2003