I used to run marathons, but after a rou
For reference only. Not medical advice.
Question
I used to run marathons, but after a rough first trimester running feels hard. What exercise is reasonable in pregnancy, and what warning signs mean stop? Real household: caregiver juggling school week and one elder or sibling nearby. Schedule: Wed; second trimester. Kitchen/home right now: walking shoes, water. Already tried: pushing through dizziness. Please answer as a practical family-care guide: what to do next tonight/today, what to avoid, and a clear decision tree. Constraints: respect «No diagnosis, no medication changes»; no dosing kids/pets/elders yourself; no mystery powders or buying prescription meds online; keep steps screenshot-friendly under ~25 minutes where cooking/care applies. Structure your help as (1) what I already tried vs better alternatives, (2) constraints/avoid list, (3) red flags—when to stop DIY and get clinical/urgent help. Keep the voice concrete and kind for a tired caregiver; stay inside kitchen/home-care/communication levers only. Name what success looks like in 24 hours without promising cures. Avoid brand shopping lists; focus on routines, food already at home, and communication scripts caregivers can screenshot.
Answer
Stop the running for now, and say the word "dizzy" out loud to your midwife or maternity team this week rather than training through it. Today you do not need an emergency number; what you need is a walking plan that stops before you feel unwell, and an answer about the dizziness.
(1) What you already tried, and the better version of it
| What you tried | Better this week |
|---|---|
| Running, and pushing through the dizziness | Brisk walking instead. The NHS pregnancy page says that if you have kept fit by running, brisk walking is a comfortable swap as the bump grows, and it is not recommended to start a new vigorous activity such as running in pregnancy. Brisk is a real training pace — it is not "doing nothing for a month". |
| Treating dizziness as a fitness problem to tough out | Treat it as a question for your clinician: blood pressure, blood sugar, iron, hydration. Those are theirs to check, not yours to guess at. |
| One long session | Short sessions, spread over the week. The same page says the aim is two and a half hours of moderate activity a week including muscle-strengthening, that you can split it into shorter sessions, and that if you cannot manage that, do what you can — any activity is better than none. Moderate means you can talk but not sing. |
The same NHS page also says: tell a trainer or instructor you are pregnant, drink water, keep cool in the right clothing, stop if you feel uncomfortable, too hot or unwell — and do not exercise on an empty stomach, because that can make you faint. (That wording is from the NHS public page "Exercise in pregnancy", checked 7 October 2026.)
Tonight and this week — under 25 minutes of your attention, all of it with what's already in the house
- Before you walk: eat something small first. Not on an empty stomach.
- Take the water bottle you already own, fill it, drink before you go out and bring it with you.
- Your walking shoes, a flat route, the cooler part of the day. 10–20 minutes is a complete session — shorter counts.
- Sit down the moment you feel light-headed. The goal is to stop early, not to reach a number.
- Keep the elder or sibling in sight: walk the same route you always walk, at a pace where you can still hear them. Do not start anything where you would be out of earshot with a dizzy turn in you.
- Write the episode down once: when it started, whether it settled within a minute or two of sitting, whether you were hot, whether you had eaten. That note is what you read out at the appointment.
- On Wednesday, or by phone before it: "I get dizzy when I run and I'm pregnant. Should I be walking only from now, and is there anything you'd want to check?" Two sentences, screenshot-ready.
I also made you a one-pager for the visit — the questions, the diary fields and the "what I am not changing" list, ready to screenshot or print: pregnancy-exercise-dizziness-onepager-3f2880cd.pdf
(2) Constraints and the avoid list
- No running, no negotiating the pace, no "one more interval".
- No new vigorous activity, and nothing with a real risk of falling or of being bumped in the tummy.
- No new powders, drops, herbal blends or anything bought online for "energy" or for the dizziness.
- No starting, stopping or doubling anything you already take, including iron, vitamins or a blood-pressure medicine. If you use a home cuff, write down the reading, the time and how you felt — that is evidence for the visit, not a reason to adjust a tablet.
- Don't get hot; don't exercise flat on your back in the later weeks; don't walk on an empty stomach; don't swim alone or in water where a dizzy turn is hard to manage.
(3) Red flags — when to stop the home plan and get help
- Dizzy once, settles within a minute or two of sitting, nothing else: sit, drink water, eat something, walk instead, mention it on Wednesday.
- Dizzy again on easy walking, or it will not settle quickly when you sit: call your maternity unit or midwife before your next session, and do not exercise again until you have spoken to them.
- Call your local emergency number now if any of these appear: fainting or nearly fainting, a racing or pounding heart, chest pain, breathlessness that is new or worse when you move, pain or swelling in one calf, any bleeding or leaking, a severe headache with blurred or flashing vision, pain high in the belly under the ribs, severe abdominal pain, or fast or difficult breathing. Say "I'm pregnant" and how many weeks along you are — those words change who comes. If you cannot reach anyone, the maternity unit's emergency department is the door.
- Water not staying down, or barely passing urine: same-day clinical contact.
What success looks like in the next 24 hours
You walk at talk pace, you feel steady, you sit down before you feel unwell rather than after, nobody in the house had to watch you instead of being cared for, and the dizziness is written down and handed to your clinician. That is not a cure and not a promise the next trimester feels easier — it is taking the guesswork out of a tired week.
The one thing I need from you
When the dizziness comes on, does it settle within a minute or two of sitting down, or do you have to lie down for it to pass? That single answer decides whether this stays a walking-and-monitoring plan or a call-before-you-exercise-again plan.
This is not a diagnosis and it does not replace your clinician: I am not diagnosing the dizziness and I am not changing anything you take. The exercise wording above is the public NHS pregnancy page, checked today; what is safe for your pregnancy is your clinician's call, and anything the library I work from does not cover, I would rather tell you than fill in.