Exercise and breastfeeding

Does exercise affect breast milk?

Moderate exercise does not appear to harm your milk supply, what's in your milk or your baby's growth. Moderate-intensity exercise of 30–45 minutes a day does not adversely affect milk volume, nutrient composition or infant growth⁵. The NHS advises that regular, moderate exercise, such as a brisk walk for 30 minutes each day, will not affect the quality or quantity of your breast milk⁶. Movement won't affect your supply as long as you're eating well and drinking plenty of fluids¹.

Vigorous or regular exercise does not harm your ability to breastfeed successfully as long as you keep up your fluids and food². Very hard exercise may make your milk taste sour for a while, and a baby might not like that². If your baby is fussy at the breast after a very hard session, try a gentler pace next time.

It's common to worry that exercise will hurt your milk or your baby's growth. Mothers can probably exercise and breastfeed without affecting their baby's growth, although this still needs confirming⁷. A good place to start is a walk at a pace where you can still hold a conversation¹.

How do you make exercise comfortable while breastfeeding?

Plan your exercise for soon after feeding or expressing, when your breasts aren't full, and wear a well-fitting, supportive bra³. Supportive footwear helps too³.

Start gently. After a straightforward birth, gentle exercise such as walking can usually begin within a few days, or as soon as you feel comfortable². Gentle stretches and pelvic floor exercises can start when you feel up to it⁶. Start slowly, build up gradually and listen to your body⁸. Exercise doesn't have to hurt to be worth doing, so if something hurts, ease off.

Walking is a good option: it's free, needs only comfortable shoes, and you can take your baby along in the pram². Over time, you can aim for about 30 minutes of gentle activity most days, at a pace where you can hold a conversation. Swimming and stretching count too¹.

How much extra do you need to eat and drink if you're breastfeeding and active?

Breastfeeding raises your energy needs and your appetite, so feeling hungrier is normal. Regular meals plus 2 to 3 small healthy snacks between meals help keep your energy up⁴. If you're a healthy weight for your height, you don't need a special diet: eat a healthy, balanced diet, drink plenty of fluids including water, and get enough rest⁶.

Water and milk are the best drinks. Aim for about 9 to 10 cups of fluid a day, and more if the weather is hot or you've been physically active⁴. Have a drink with each breastfeed¹. Keep water within reach, and take it with you when you go walking.

Tea and coffee count towards your fluid. Have no more than 4 cups of tea or instant coffee (or 3 cups of plunger coffee) a day, and avoid energy drinks. It's best to avoid alcohol⁴.

Don't skip meals or cut right back on food when you start exercising: that combination has been linked with a rare but serious condition called lactation ketoacidosis⁹. Talk to a doctor or dietitian before cutting out foods or trying to lose weight while breastfeeding.

When to check with a health professional

If you're starting exercise after a long break, it's always a good idea to see your doctor first.

For an injury or a health condition, see a health professional, such as your doctor or a physio.

If your birth was complicated or you had a caesarean, recovery takes longer, so talk to your midwife or doctor before doing anything strenuous.

Call your local emergency number for chest pain or pressure (or pain spreading to the arm, neck, jaw or back, especially with sweating or feeling sick), severe breathlessness, fainting or collapse, signs of a stroke, a serious injury, or someone who isn't safe.

After birth, bleeding, fluid leaking, regular painful contractions, the baby moving less, calf pain or swelling, or a bad headache or changes in vision need the midwife, doctor or maternity unit straight away, even if they seem mild. Heavy bleeding is also an emergency.

If exercise feels too hard, or you get muscle aches, strains or pains, or breast lumps or tenderness, ease off or stop. See a doctor, midwife or women's health physiotherapist if they persist². If you feel dizzy or unwell during exercise, stop, and see a doctor if it is mild and passes. Sore muscles a day or two later are normal. If you feel unusually tired, get it checked by a doctor rather than pushing on.