If you are taking a GLP-1 medication, or thinking about it, and your knees ache, you may be hoping that losing weight will ease them. For many people, it does help. Pairing weight change with the right kind of movement can make an even bigger difference to how your knees feel.

How weight affects your knees

Every step you take puts more than your body weight through your knees. That means even small changes in weight can make a noticeable difference. In one study of adults with knee joint changes, each kilogram of weight lost took around four kilograms of load off the knee with every step.

In a recent trial of people with knee osteoarthritis and higher body weight, those taking a GLP-1 medication had a greater improvement in knee pain than those taking a placebo, alongside their weight loss.

Weight loss can also help with the inflammation that often plays a part in long-term knee pain. Fat tissue releases substances that can add to inflammation in the joints, so losing some can help on that front too.

Why muscle matters as your weight changes

When you lose weight, some of what you lose is muscle, not just fat. With GLP-1 medications, research suggests this can be a significant share of the weight lost. Your thigh muscles act like shock absorbers for your knees, so keeping them strong is especially important.

Strength exercises, alongside eating enough protein, may help protect muscle while you lose weight. This means your knees can benefit from less load and good muscle support at the same time.

Building knee strength

Something to try two or three times a week:

• Sit-to-stand. Rise from a chair without using your hands, then lower yourself slowly.
• Step-ups. Step up onto the bottom stair and down again, holding the banister.
• Heel raises. Rise onto your toes, pause, then lower slowly.
• Bridges. Lie on your back with your knees bent, lift your hips, then lower them slowly.

If you would like to follow along, VIDA has short videos of sit to stands, heel raises and bridges you can work through at your own pace. Start with a few repetitions and build up gradually.

A mild ache during exercise that settles by the next day is usually fine.

Moving more as your weight changes

As your weight changes, you may find moving gets easier, and that is a great time to build up your activity. Walking is a good foundation. Some ideas for building up gradually:

• Start with short walks and add a few minutes each week.
• Spread walks across the day rather than doing one long one.
• Choose flatter routes to begin with, adding gentle hills as your knees get stronger.
• Mix in swimming, cycling or water exercise, which take some of your weight.

Looking after your energy

GLP-1 medications reduce your appetite, which can mean you eat less overall. Some people notice they feel more tired or light-headed, especially early on or after a dose increase. Planning your more active sessions for times when you have eaten, staying well hydrated and building up gently can help.

Eating enough protein, from foods like eggs, fish, chicken, beans, lentils, tofu and yoghurt, helps your muscles recover from exercise. If you are finding it hard to eat enough, or feel dizzy or unwell when you exercise, it is worth speaking to your prescriber.

Easing knee pain day to day

A few changes can help your knees feel more comfortable while you build strength:

• Take stairs one at a time, leading with your stronger leg going up and your sorer leg going down.
• Choose supportive, cushioned shoes for walking.
• Get up and move every half hour or so if you sit for long periods.
• Use warmth on a stiff knee before activity.

If you are still deciding

If you are considering a GLP-1 medication, now is a good time to start building knee strength. Stronger thigh muscles will help your knees whatever you decide, and if you do start treatment, you will already have habits in place to help protect your muscles as your weight changes. Sit to stands and heel raises a few times a week, and a regular short walk, are a good place to begin.

Keeping track

Your VIDA pain check-in is a good way to notice how your knees change as your weight and activity shift over time.

What to take away

• Small changes in weight can take a lot of load off your knees.
• Strength exercises help protect muscle as your weight changes.
• Build up walking gradually, spreading it across the day.
• Eat enough protein and plan activity for when you have eaten.
• Speak to your prescriber if you feel dizzy or unwell when exercising.

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