For most people with a healthy, low-risk pregnancy, the answer to "can I still train?" is yes — and staying active is one of the better things you can do for yourself and your baby. The trick is knowing what to adjust, when to adjust it, and which symptoms mean stop. This is a practical guide to doing exactly that, trimester by trimester.
What the guidelines actually say
The headline number from the American College of Obstetricians and Gynecologists (ACOG) is 150 minutes of moderate-intensity aerobic activity per week, spread across most days — the same target as for non-pregnant adults. That's five 30-minute sessions, or you can break it into 10-minute chunks if that fits your day better. Strength training counts too, and there's no rule that says you have to give up lifting.
Before you start or continue, get the green light from your provider, especially if you have a condition like pre-eclampsia, placenta previa, cervical insufficiency, or a multiple pregnancy — these are situations where exercise may be restricted. Assuming you're cleared, the bigger question is how to train, not whether to.
Forget the 140 bpm rule
You may have heard that your heart rate should never cross 140 beats per minute while pregnant. That cap was dropped from the guidelines decades ago — it was too blunt and ignored individual fitness. Use the talk test instead: at a moderate effort you should be able to hold a conversation but not sing. If you can only get a few words out between breaths, ease off. On a 6-to-20 rating of perceived exertion (RPE) scale, aim for roughly 12 to 14 — "somewhat hard," not all-out.
How to adjust by trimester
Pregnancy isn't one phase, and your training shouldn't be either. Relaxin loosens your joints, your centre of gravity shifts forward, and blood volume climbs by close to 50% — all of which change how movement feels. If you want the mechanics behind why your body responds differently month to month, our piece on how hormones affect training and recovery goes deeper.
| Stage | Focus | Key modifications |
|---|---|---|
| First trimester (wk 1–13) | Maintain your routine | Train as usual if you feel up to it. Fatigue and nausea are the main limiters — scale volume, not effort, on rough days. Stay well hydrated. |
| Second trimester (wk 14–27) | Adapt and reduce impact | Switch loaded barbell work to dumbbells or machines. If you feel dizzy or lightheaded lying flat (roughly from week 16), prop your torso up on an incline or sit up. Stop deep core flexion like full sit-ups. |
| Third trimester (wk 28–40) | Mobility and stability | Favour walking, swimming, and stationary cycling. Widen your stance for balance, shorten range where the bump gets in the way, and build in more rest between sets. |
What's worth keeping in your program
Aerobic base work is the easiest win: brisk walking, swimming, water aerobics, and stationary cycling are low-impact and easy to scale. Swimming is especially kind in the third trimester because the water takes load off your joints and back.
Strength training deserves a place too. Keep compound movements that don't pin you flat on your back or strain your midline — goblet squats, supported rows, lat pulldowns, glute bridges, and step-ups all travel well through pregnancy. A simple rule: drop the load so you finish every set with two or three reps in reserve, and never grind a rep. You can find scalable versions of most of these in our exercise library.
Train the pelvic floor and deep core
This is the part most general fitness advice skips. Your pelvic floor supports the growing weight above it and plays a direct part in delivery and recovery. Practise contractions daily: squeeze as if stopping the flow of urine, hold for 5 to 10 seconds, then fully relax for the same length — the release matters as much as the squeeze. Aim for two or three sets of 10. Pair that with gentle deep-core work like bird-dogs and side planks, and learn to exhale on exertion rather than holding your breath and bearing down.
Form cues that matter more now
- Breathe out on the hard part. Holding your breath spikes intra-abdominal pressure, which pushes against an already-stretched midline and pelvic floor. Exhale as you lift, push, or stand up.
- Watch for coning. If a ridge or dome bulges down the centre of your belly during an exercise, that movement is too much load for your abdominal wall — regress it. This helps limit the gap (diastasis recti) you'll work on afterward.
- Change positions slowly. Lower blood pressure and pooling make standing up quickly a recipe for dizziness. Move deliberately between lying, sitting, and standing.
- Keep loads stable and predictable. Looser joints mean less margin for a wobble. Choose machines or dumbbells over anything that punishes a balance slip.
Signs to stop and call your provider
Most sessions will feel fine. But stop exercising and seek advice if you notice any of these, which ACOG flags as warning signs:
- Vaginal bleeding or fluid leaking
- Regular, painful contractions
- Chest pain, or a headache that won't shift
- Dizziness or feeling faint that doesn't pass with rest
- Calf pain or swelling on one side
- Shortness of breath before you've even started
- Muscle weakness affecting your balance
None of these mean you did something wrong — they mean your body is asking you to pause and check in.
Fuelling and hydration
You don't need to "eat for two," but you do need enough to support the work. In the second and third trimesters, demands rise by roughly 340 and 450 calories a day respectively — a real but modest bump, and exercise adds a little more. Prioritise protein and iron-rich foods, drink water before you feel thirsty, and don't train fasted if it leaves you shaky. For balanced, easy options, browse our recipes. Overheating is the other thing to manage: skip hot, humid rooms and hot yoga, wear breathable layers, and cool down if you feel flushed.
Keeping it sustainable
Consistency beats intensity here by a wide margin. Three or four moderate sessions you actually look forward to will serve you better than an ambitious plan you abandon by week 20. Listen to the day in front of you — energy swings are normal, and a walk on a tired day still counts toward your 150 minutes.
The work you do now also sets up an easier return later; how you rebuild afterward is its own skill, covered in postpartum fitness: easing back in safely. Whatever tool you use, the goal stays the same: move often, stay comfortable, and stop when your body tells you to.
Key takeaways
- Aim for ACOG's 150 minutes of moderate activity a week; get cleared by your provider first.
- Drop the old 140 bpm cap. Use the talk test and RPE 12-14 to judge effort.
- Adjust by trimester: maintain early, reduce impact mid, prioritise stability late.
- Exhale on exertion, watch for belly coning, and train the pelvic floor daily.
- Stop and call your provider for bleeding, contractions, chest pain, or faintness.
Frequently asked questions
Can I keep lifting weights while pregnant?
Yes, if your pregnancy is low-risk and your provider agrees. Swap loaded barbell work for dumbbells or machines, leave two to three reps in reserve, and breathe out as you lift instead of holding your breath.
Is it safe to exercise lying on my back?
It is fine early on, but from around week 16 the weight of the uterus can press on a major vein and make some people feel dizzy. If lying flat brings on lightheadedness, prop your torso up on an incline or sit up instead.
How hard should I push during a workout?
Moderate, not maximal. You should be able to talk in full sentences but not sing, which maps to roughly 12 to 14 on the 6-to-20 perceived exertion scale. If you can only manage a few words at a time, ease off.