You are training consistently. You are eating well. But the results have plateaued. Adding more sessions, more sets, more intensity is not moving the needle the way it used to.
This is a biology problem, not a discipline problem.
What actually drives training adaptation
Muscle growth and body composition change are not simply a function of training stimulus. They are the result of a biological environment responding to that stimulus. The same training programme delivers very different outcomes depending on:
- Hormonal status (testosterone, growth hormone, IGF-1, cortisol, oestrogen)
- Insulin sensitivity and glucose regulation
- Sleep quality, particularly deep sleep where most adaptation occurs
- Inflammatory state and recovery capacity
- Nutritional status at a micronutrient level, not just caloric balance
When these underlying factors are suboptimal, adding more training load produces diminishing returns, and eventually, diminishing function.
The hormonal environment
Testosterone is the primary anabolic hormone driving muscle protein synthesis in response to training. In men, testosterone levels typically begin declining from the early 30s. By the mid-40s, many men have a meaningfully different hormonal environment than they did at 25, which directly affects how their bodies respond to the same training stimulus.
This is not about being “old”. It is about understanding that your training programme may need to account for a changed hormonal context.
In women, the hormonal picture is more complex. Oestrogen has anabolic effects on muscle and connective tissue. Progesterone affects fluid retention and recovery. The fluctuations across the menstrual cycle, and the more pronounced shifts during perimenopause, create variable recovery and adaptation windows that most generic training programmes ignore entirely.
Growth hormone and IGF-1 govern a significant portion of the cellular repair and remodelling that constitutes adaptation. They peak during deep slow-wave sleep. People who are chronically sleep-deprived or whose sleep architecture is disrupted, including by hormonal imbalance, are losing the recovery phase that makes training productive.
Cortisol and the training balance
Cortisol is a catabolic hormone. It breaks down tissue, including muscle, and it is necessarily elevated during training. The adaptation benefit comes in the recovery phase, when cortisol falls and anabolic hormones drive repair.
When cortisol is chronically elevated, including from psychological stress, poor sleep, or excessive training volume, the catabolic phase is prolonged and the anabolic recovery phase is suppressed. The result can be a flat or even declining body composition trajectory despite consistent effort.
Insulin resistance and body composition
Insulin resistance is more common than most people realise, and it is not limited to people with elevated blood glucose. Subclinical insulin resistance means the body is less efficient at shuttling glucose into muscle cells and more efficient at storing it as fat. This directly affects body composition, even in people who train hard and eat reasonably well.
Identifying and addressing insulin resistance, through a combination of dietary approach, metabolic support, and, if deemed clinically appropriate, specific therapeutic intervention, may help improve the composition response to training. Individual results vary.
What a thorough assessment covers
If your training results have plateaued, a comprehensive biological assessment typically evaluates:
- Hormonal markers: testosterone (total and free), growth hormone axis (IGF-1), cortisol, oestradiol, SHBG
- Metabolic function: fasting insulin, HbA1c, fasting glucose, lipid profile
- Thyroid: TSH, Free T3, Free T4
- Nutrient markers: ferritin, vitamin D, B12, magnesium, zinc
From this picture, a practitioner may identify factors worth exploring further and, if clinically appropriate, design a protocol around what the assessment finds. Outcomes are individual and cannot be guaranteed.
This is not about replacing training
Training is essential. It provides the stimulus. But the biological environment determines how well you respond to that stimulus. Optimising the environment is how you get more from the effort you are already putting in.
Training hard but not seeing the results? Start your free assessment. A practitioner reviews your health picture and your goals.
Disclaimer: Individual results vary. All protocols are subject to practitioner assessment and clinical suitability. Nothing in this article constitutes medical advice.
