Why Your Workouts May Feel Different During Pregnancy

Quick note before we dive in: I'm a certified pre and postnatal personal trainer — but I am not your doctor. Everything in this post is intended for educational purposes only and should not be taken as medical advice, diagnosis, or treatment. Every pregnancy is different, and your healthcare provider is always your most important resource. Consult them before beginning or modifying any exercise program.

I went to Pilates this week, at 24 weeks pregnant. My balance was off, my core wouldn’t engage the way it normally does, and modifications were plentiful. Even though I knew the physiological reason behind every single thing I was experiencing, it still caught me off guard. I walked out of that class…humbled.

So let’s talk about what’s actually happening — and more importantly, what to actually do about it, because information without application is just trivia.

The American College of Obstetricians and Gynecologists (ACOG) recommends "women with uncomplicated pregnancies... engage in aerobic and strength-conditioning exercises before, during, and after pregnancy." Movement during pregnancy (as long as there are no contraindications) is not just safe — it’s encouraged. It just may look different. And knowing the why makes the difference between modifying with confidence and feeling like your body is betraying you.

As a reminder, you may not feel ALL the shifts below currently, and you may not need to apply ALL the practical shifts, so take the information that is helpful to you, and leave the rest!

1. Your Balance Feels Off

As your baby grows, your center of gravity shifts forward. Your posture adjusts to compensate. Everything you’ve trusted your body to do automatically — a lunge, a step off a curb, standing on one leg — suddenly requires actual concentration. I used to dance competitively and professionally. I still trip walking down the street on a good day. Pregnancy made that significantly more apparent!

Practical shifts:

• Widen your stance. A wider base of support could make all the difference.

• Keep a hand on a wall or rack for anything that challenges your balance.

• Swap single-leg movements for bilateral ones when needed.

• Slow down direction changes.

• And give yourself grace... Probably the hardest to apply of all...

2. Your Heart Rate Is No Longer Your Best Guide

Your blood volume increases by up to 50% during pregnancy. Your heart is working significantly harder to supply both you and your baby — which means your heart rate climbs faster and sits higher than it did before, even at the same effort level. Using heart rate zones that worked pre-pregnancy can potentially mislead you.

Practical shifts:

• Switch to Rate of Perceived Exertion instead. On a scale of 1–10, aim for a 5–7.

  • The easiest field test: the talk test. Can’t get a word out = dial your effort back. Could sing the full chorus of a song = you have more room to work.

3. Your Core Feels Disconnected

As your uterus expands, the two halves of your rectus abdominis separate along your midline to make room. This is completely normal (and pretty incredible, if you ask me!). It also means your core functions differently — less connected, less able to manage load — and certain movements can create more harm than good.

Watch for coning or doming — a visible ridge or peak along your midline during exercise. That’s your body telling you the load is too much right now.

Practical shifts:

• If you see coning or doming, regress the movement — not your effort, just the movement.

• Reconsider traditional crunches, sit-ups, and full planks as pregnancy progresses. There are so many wonderful exercises you could do for your core during this season.

• Focus on deep core breathing and diaphragmatic work. This isn’t just about now — it’s the foundation of your postpartum recovery.

4. Your Joints Are More Vulnerable Than Usual

Your body produces a the hormone relaxin during pregnancy. It loosens your ligaments to prepare your body for birth. It doesn’t selectively loosen only the ones you want loosened. Every joint becomes more mobile and more vulnerable as a result. Your body may actually feel more flexible than usual. That openness is not progress. It’s vulnerability.

Practical shifts:

• This is not the season to push range of motion or try new flexibility work. Prioritize stability and control over range.

• Slow your movements down.

• Avoid ballistic or high-impact loading on joints that have less support than usual. Intentional and controlled is the goal right now.

5. The Breathlessness Is Real

Rising progesterone increases your breathing rate and your sensitivity to carbon dioxide. Your oxygen needs have gone up significantly. Your heart and lungs are working harder than usual to meet them — even at rest.

Practical shifts:

• Let go of pace, distance, and performance metrics for now. Use the talk test as your guide.

• Build in longer rest periods between sets.

6. You Feel Like You're Running Hotter

Pregnant women run warmer, sweat faster, and overheat more quickly. Your body is generating more heat and working harder to dissipate it. Most women don’t connect early fatigue and dizziness during workouts to temperature regulation — but it’s one of the most common culprits.

Practical shifts:

• Hydrate before you feel thirsty.

• Exercise during cooler parts of the day when possible.

• Be cautious with heated studios, hot yoga, and outdoor summer workouts.

7. Round Ligament Pain

The round ligaments support your uterus and stretch as it grows. Quick direction changes, sudden movements, or sneezing without bracing can pull them abruptly — causing a sharp, shooting pain in your lower abdomen or groin that stops you mid-step.

It’s alarming. It was for me, especially as a loss mom, for who any unexpected physical sensation can send fear through the roof.

Practical shifts:

• Slow down direction changes and position transitions.

• Warm up longer.

• Bracing gently before movements that tend to trigger it can help.

8. Symphysis Pubis Dysfunction & SI Joint Pain

Symphysis Pubis Dysfunction (SPD) happens when the joint at the front of your pelvis becomes unstable due to relaxin and the increased load of pregnancy. It can range from mild discomfort to genuinely debilitating pain.

SI joint pain shows up at the back of the pelvis and usually presents as deep ache in your lower back, one side of your glutes, or down the back of your leg. Similar to SPD, it's driven by relaxin loosening the ligaments that normally keep that joint stable.

SPD and SI joint pain are both forms of Pelvic Girdle Pain. The practical modifications are similar regardless of where yours presents, but if the pain is significant, a pelvic floor physical therapist can pinpoint exactly what's going on and give you targeted treatment.

Practical shifts:

• Avoid unilateral loading — swap lunges for squats, single-leg work for bilateral variations.

• Skip deep lateral stretches and wide stance movements.

• Keep knees together when getting in and out of cars, turning in bed, stepping over things.

• Symmetrical movement is your best friend.

9. First Trimester Fatigue Is Not Laziness

The fatigue of early pregnancy is not regular tiredness. It is cellular-level exhaustion — driven by progesterone surges, rapid blood volume expansion, and the staggering energy demands of building an entirely new human being from scratch.

You are not lazy. You are not losing fitness. Your body is doing something extraordinary.

Practical shifts:

• Shorten sessions before cutting them entirely.

• Find your highest-energy window and protect it for movement.

• Remember that rest is productive in the first trimester. Give yourself permission to receive that.

10. Lying Flat on Your Back Needs to Change After 20 Weeks

After about 20 weeks, lying flat on your back can compress the vena cava — a major vein that returns blood to your heart — reducing circulation to both you and your baby. Dizziness, nausea, and lightheadedness during floor work are your signals that this is happening.

Practical shifts:

• Elevate your upper body on a wedge or bench for floor-based work.

• Shift to side-lying variations where possible.

• Adapt movements to seated or standing alternatives.

• If you feel dizzy during any supine exercise — roll to your left side first, then sit up slowly.

The Whole Point

Your body is not failing you. It is not betraying you. It is not weaker than it was. It is doing something it has never done before — or something it is doing again, with all the complexity that carries — and it deserves to be met with information, patience, and the kind of practical support that actually helps.

I’m living through most of these right now. Some days I nail every modification. Some days I do half of what I planned and call it a win.

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Questions? Feel free to DM me or drop them below.