Why Do We Get More Tired as We Age?
“Dr Max Gowland, biochemist and longevity expert explains the importance of ageing with grace from within”
Have you ever found yourself saying, “I just don’t have the energy I used to have”?
If so, you’re certainly not alone. Feeling more tired is one of the most common complaints as we get older. Many of us notice that we can’t do quite as much as we once did without needing a rest, and those afternoon energy slumps seem to arrive more frequently than they used to. It’s tempting to put this down to age and simply accept it as part of getting older. But what if there is more to the story? What if that tiredness is actually telling us something about what is happening inside our bodies?
The reality is that fatigue is rarely caused by one thing. Instead, it is usually the result of several biological changes occurring at the same time. Changes in our muscles, hormones, sleep patterns, metabolism, immune system and even the tiny power stations inside our cells can all contribute to feeling less energetic.
The encouraging news is that many of these changes can be influenced by the choices we make every day.
Our Cellular ‘Power Stations’ Start to Slow Down
Inside every cell in our body are tiny structures called ‘mitochondria’. These are often described as the body’s power stations because they convert the food we eat and the oxygen we breathe into the energy that powers every movement, thought and bodily process. As we age, these mitochondria become less efficient. But there is another problem too. Some of them simply disappear over time.
Research shows that both the number and quality of these mitochondria decline with age, particularly in our muscles, which happen to contain the most mitochondria within our body. This means our cells have fewer power stations available to generate energy and the ones that remain, do not work as efficiently as they once did.
Imagine a town where several power stations have closed and the remaining ones are operating below capacity. The lights stay on, but there is less energy available whenever demand increases. The same thing can happen within our bodies. As a result, we may find ourselves becoming tired more easily, recovering more slowly from physical activity and struggling with tasks that once seemed effortless.
The good news is that our mitochondria respond remarkably well to lifestyle changes. Regular physical activity, especially walking, cycling and resistance training, stimulates the production of new mitochondria in all our cells. Scientists call this ‘mitochondrial biogenesis’, but all it really means is that our bodies can build new power stations when we give them a reason to do so.
Losing Muscle Also Means Losing Energy
Have you ever wondered why carrying the shopping, climbing stairs or spending a few hours gardening seems harder than it used to? Part of the answer lies in our muscles.
From around the age of 40 onwards, we gradually begin to lose muscle mass and strength, unless we actively work to maintain it. This age-related muscle loss is known as ‘sarcopenia’, and unfortunately it tends to accelerate faster as we get older.
Muscle is not just there to help us move. It is one of the most metabolically active tissues in the body, helping to regulate blood sugar levels, supporting our overall mobility and acting as an important reserve of strength and energy. But as muscle mass declines, everyday activities require a greater proportion of our remaining strength. The result is that simple tasks begin to feel more demanding and more tiring. It’s natural.
But Government nutrition surveys consistently show that many older adults are not regularly consuming enough high-quality protein in their diet. Combine this deficiency with a lack of resistance exercise, then muscle loss will accelerate.
The solution is surprisingly straightforward. Many scientific studies show that regular strength-based exercise combined with adequate protein intake can help preserve muscle, maintain independence and support healthy energy levels. Even balance is improved, which in turn will help reduce the risk of falling as we age. This may sound relatively unimportant, but falls are one of the greatest threats to health and independence as we get older. In fact, falls are a leading cause of injury-related hospital admissions and deaths in older adults. What starts as a simple loss of balance can result in a broken hip, loss of mobility, a prolonged hospital stay and, for some people, a rapid decline in overall health.
Sleep Is Not Always What It Used to Be
Most of us notice changes in our sleep as we get older. We may wake more often during the night, find it harder to stay asleep or wake earlier than we would like. Even when we spend the same number of hours in bed, the quality of our sleep often declines. But poor sleep affects virtually every aspect of our health, not just our energy levels. It reduces mental sharpness, affects mood, impairs memory and leaves us feeling physically drained. Poor sleep has also been shown by scientists to be associated with a higher risk of cardiovascular disease, diabetes and even certain cancers!
Sleep disorders such as sleep apnoea also become more common with age and can significantly reduce daytime energy levels. If you regularly wake feeling tired, despite a full night’s sleep, snore heavily or experience excessive daytime fatigue, it may be worth discussing this with your GP. Never underestimate the importance of good sleep. It remains one of the most powerful natural energy boosters available to us.
Nutrient Deficiencies Can Also Leave Us Running on Empty
Another common reason for fatigue is simply poor nutrition. As we age, our ability to absorb certain nutrients often declines, some being required for energy production. One of the best examples is with vitamin B12. Many older adults produce less stomach acid than they once did, making it harder to extract vitamin B12 from food. Because B12 is essential for energy production, nerve function and red blood cell formation, low levels can leave us feeling tired, weak and mentally sluggish. Other nutrients linked to fatigue include iron, vitamin D, magnesium and folate, all of which are known to be sub-optimal in our diet as we age. Clearly regular supplementation with a multi-nutrient high quality formulation, specific to the over 50s, can help reduce these potential nutrient deficiencies. This is particularly important for vegans who will require regular supplementation in order to reach required levels of some of these nutrients.
One of the challenges of ageing of course, is that although we generally need fewer calories, our need for vitamins and minerals remains the same and sometimes even increases. In other words, we need more nutrition from less food, which is hard. These various micronutrients play a large number of important roles besides supporting energy production, so ensuring you get enough from your food and possibly supplements, is very important.
This is why diet becomes increasingly important as we get older. A dietary pattern rich in vegetables, fruits, legumes, nuts, seeds, fish, eggs and quality protein sources provides many of the nutrients needed to support healthy energy production.
The Hidden Impact of Blood Sugar Control
Many people experience what they describe as energy ‘crashes’ during the day, where they will suddenly feel tired for no obvious reason. One possible explanation is ‘insulin resistance’. When our cells become less responsive to insulin, blood sugar regulation becomes less efficient. Blood glucose can then rise rapidly after a meal and then fall more sharply afterwards, leaving us feeling hungry, tired and lacking concentration.
Insulin resistance becomes increasingly common with age, particularly in those carrying excess weight around the abdomen or living a sedentary lifestyle. When insulin resistance becomes severe, it can eventually develop into type 2 diabetes, a condition that sits at the centre of many age-related health problems and can significantly affect long-term health and wellbeing.
Improving diet quality, increasing physical activity and maintaining muscle mass can significantly improve insulin sensitivity and help stabilise energy levels throughout the day.
Inflammageing: The Silent Energy Thief
There is another less obvious reason why our energy levels can decline as we age. Scientists call it ‘inflammageing’, which in essence, is age related chronic inflammation.
This rather awkward term describes the low-grade chronic inflammation that gradually develops within our bodies over time. And unlike the inflammation that helps us recover from injury or infection, this unhealthy inflammageing quietly smoulders away in the background for years.
Researchers now believe this persistent inflammatory burden contributes to many age-related diseases and may also be a major driver of fatigue. Inflammation places constant demands on our immune system and can interfere with normal mitochondrial function, making energy production less efficient.
The good news is that many of the lifestyle habits that support healthy ageing also help reduce inflammation. Regular exercise, maintaining a healthy weight, eating plenty of plant foods and avoiding smoking can all make a real difference.
Hormones Change Too
Our hormones also influence how energetic we feel. As we age, levels of hormones such as testosterone, oestrogen and growth hormone gradually decline. As these hormones help regulate muscle mass, metabolism, recovery and overall vitality, you can see why hormonal decline can cause fatigue.
For women in particular, the hormonal changes associated with menopause can also affect sleep quality, mood and overall energy levels. While these hormonal changes are just a natural part of ageing, many of their effects can be alleviated through good nutrition, regular exercise, maintaining muscle mass and prioritising sleep.
The Bottom Line
In summary, feeling more tired as we age is not caused by just a single factor. It is usually the result of several biological changes occurring together, including declining mitochondrial function as we discussed, loss of muscle, poor sleep, nutrient deficiencies, insulin resistance, chronic inflammation and hormonal changes.
The important message is that while getting older is inevitable, becoming permanently tired is not.
Our energy levels are influenced by how well we sleep, how much muscle we maintain, what we eat, how active we are and how effectively our cells produce energy. The sooner we start looking after these areas, the better our chances of staying active, independent and full of life for years to come.
We may not be able to stop the ageing process, but we can certainly influence how energetically we travel through it.