What happens to your body during perimenopause
Nicola Tik
Perimenopause is the transition period leading up to the end of menstrual cycles, and it can bring a range of physical changes that are not always well explained or easy to anticipate. Many of these changes have a direct effect on the muscles, joints, and connective tissue of the body. This article explains what is happening and why the MSK system is particularly affected during this transition.
The physical changes of perimenopause are driven largely by fluctuating levels of oestrogen, the hormone that plays a central role in regulating many of the body's systems beyond reproduction. During perimenopause, oestrogen levels do not simply decline steadily. They fluctuate, sometimes significantly, before eventually settling at a lower level. It is this fluctuation, as much as the overall decline, that drives many of the physical changes of the transition period.
Oestrogen has a direct influence on joint health, muscle maintenance, pain sensitivity, and the integrity of connective tissue. When its levels become unpredictable, the systems it regulates become unpredictable too, which is why the physical experience of perimenopause can feel inconsistent and difficult to anticipate from one week to the next.
Oestrogen plays an important role in maintaining the health of joint tissue, including the cartilage that cushions joints and the synovial fluid that keeps them lubricated. When oestrogen levels fluctuate, joints can become less well lubricated and more reactive to load, which produces the stiffness, aching, and swelling that many people notice in their hands, knees, hips, and lower back during perimenopause.
Joint symptoms during perimenopause often feel different from the joint pain associated with injury or overuse. They tend to be more widespread, more variable, and less clearly connected to any specific activity or loading pattern. Many people find that their joints feel stiff and uncomfortable on some days and perfectly manageable on others, without any obvious change in what they have been doing. This variability is a characteristic feature of oestrogen-driven joint changes and is worth understanding as such rather than trying to find a specific mechanical explanation for every flare.
Oestrogen also plays a role in maintaining muscle mass and supporting muscle recovery after effort. As oestrogen levels fluctuate and begin to decline during perimenopause, the body's ability to maintain and build muscle becomes less efficient. Muscles may feel less responsive than they used to, recover more slowly after physical effort, and fatigue more quickly under the same level of demand.
This gradual change in muscle capacity is one of the less visible but more significant physical shifts of perimenopause. It does not happen suddenly, and many people attribute the change to general ageing or reduced fitness rather than recognising it as a direct consequence of hormonal fluctuation. Understanding the connection makes it easier to respond to it appropriately, particularly around the role of strength-based movement in maintaining muscle during this period.
Oestrogen has a moderating effect on pain sensitivity. When levels are stable, it helps regulate how the nervous system processes and responds to pain signals. When oestrogen fluctuates, that moderating effect becomes inconsistent, and the body can register pain more readily than it would during periods of hormonal stability.
This means that during perimenopause, existing aches and discomforts can feel more prominent, and new ones can appear that have no clear structural cause. The lower back, hips, knees, and hands are the most commonly affected areas, but the pattern varies considerably between individuals. Research suggests that musculoskeletal pain is one of the most frequently reported symptoms of perimenopause, though it receives considerably less attention than other symptoms such as sleep disruption and mood changes.
Sleep disruption is a common feature of perimenopause, driven by hormonal fluctuation affecting sleep architecture and, in many cases, by night sweats that interrupt sleep quality and duration. The effect of disrupted sleep on the MSK system is significant. Muscles repair during sleep, pain sensitivity recalibrates during sleep, and the body's capacity to manage load the following day depends partly on the quality of recovery it has had overnight.
Fatigue during perimenopause is also not simply a consequence of poor sleep. Oestrogen fluctuation affects energy regulation more broadly, and many people find that their overall energy reserves feel less reliable than they used to, with physical effort feeling more demanding and recovery taking longer than expected. Understanding this as a physiological reality rather than a personal failing makes it easier to adjust activity and expectations in a way that supports the body through the transition rather than working against it.