Strength Training: Build Muscle Without Harming Fertility

You may wonder if building muscle through strength training could harm your fertility. This concern is valid, especially as you seek to balance your health goals with your hopes for a family. In the United States, infertility affects about 10–15% of couples, and both lifestyle and exercise habits play a role in reproductive health. Two extra hours of moderate strength workouts a week can raise pregnancy odds by 15%, yet five hours of “all-out” lifting may slash them by 32%.

Current research offers encouraging news: moderate strength training, when done safely and appropriately, does not harm fertility and may even support it. For men, regular resistance or combined aerobic and strength training can improve semen quality, hormonal balance, and pregnancy rates, especially in those with lifestyle-related fertility challenges.

For women, supervised strength training during pregnancy is linked to better musculoskeletal health, reduced risk of gestational diabetes, and improved mental well-being, without negative effects on fertility when performed with proper guidance. The key is moderation; excessive or extreme training can disrupt hormones and reduce fertility, but balanced routines are safe and beneficial for most people.

Why can strength training boost fertility for some people and harm it for others?

Strength training can boost fertility for some people while harming it for others due to differences in exercise intensity, individual health status, and underlying biological mechanisms. Moderate strength training improves fertility by enhancing hormone balance, reducing inflammation and oxidative stress, and supporting healthy metabolism and cardiovascular function. These benefits can lead to better semen quality in men and improved hormonal regulation in women, especially for those with lifestyle-related fertility challenges such as obesity or insulin resistance.

However, excessive or intense strength training can disrupt the delicate hormonal axis that controls reproduction, leading to lower testosterone in men, menstrual irregularities in women, and reduced ovarian reserve. Overtraining may also increase oxidative stress and inflammation, further impairing reproductive function. The use of performance-enhancing drugs or anabolic steroids, sometimes associated with strength sports, can severely disrupt hormone production and fertility.

Here’s the physiology:

• Moderate lifting raises muscle-building hormones (IGF-1) without tanking reproductive signals (LH, FSH).
• Overtraining plus calorie gaps spikes cortisol, which can shut down the hypothalamic-pituitary-ovarian axis, leading to luteal phase defects or anovulation.
• For men, sensible lifting bolsters testosterone, but extreme regimens—or anabolic steroids—cut sperm counts.

Additionally, individual factors; such as baseline fitness, age, and pre-existing reproductive health, affect how your body responds to training. In summary, strength training supports fertility when balanced and tailored to your needs, but excessive or poorly managed routines can have the opposite effect.

Need a deeper dive on balancing exercise and hormones? Visit Exercise vs. Fertility: Finding the Sweet Spot.

How much strength training is “fertility-friendly” each week?

Fertility-friendly strength training means choosing a routine that is moderate in intensity, tailored to your needs, and supervised by a professional when possible. Recent research highlights that individualized programs, designed with your health status and goals in mind, are safest and most effective. For most people, engaging in strength training two to three times per week, with proper technique and attention to rest and recovery, supports fertility and overall well-being. Aim for 2–3 full-body sessions lasting 30–45 minutes.

It is important to avoid excessive intensity or duration, as overtraining can increase risks. Always consult with a healthcare provider or fitness professional to ensure your plan is appropriate, especially if you have pre-existing conditions or are pregnant. Safe practices, including gradual progression and monitoring for signs of strain or injury, help maximize benefits and minimize risks.

Want a ready-made schedule? Check the Low-Impact Workout Calendar: 30-Day TTC Plan.

What are the warning signs that you’re overtraining or under-fueling while TTC?

When you are trying to conceive (TTC), warning signs of overtraining or under-fueling can be subtle but important to recognize. Persistent fatigue, decreased performance, and lack of progress in your workouts are key red flags that your body is not recovering properly. For women, missed or irregular periods, and for men, reduced libido or changes in sexual function, may signal hormonal disruptions linked to overtraining or low energy availability. Other symptoms include trouble sleeping, mood changes such as irritability or depression, frequent illnesses, and increased injuries or muscle soreness that does not resolve with rest.

Under-fueling; also known as low energy availability, can overlap with overtraining and may cause additional issues like unexplained weight loss, digestive problems, and feeling cold more often. Both overtraining and under-fueling can disrupt the hypothalamic-pituitary axis, leading to hormonal imbalances that impair fertility. If you notice these symptoms, it is important to adjust your training, increase your calorie intake, and seek guidance from a healthcare provider or registered dietitian familiar with fertility and sports nutrition. Early recognition and intervention can help restore balance and support your reproductive health.

If any boxes above get ticked, scale back and skim Overtraining Warning Signs: When Workouts Hurt Fertility.

Which strength exercises build muscle and support conception safely?

To safely build muscle and support conception, focus on strength exercises that use major muscle groups, emphasize good form, and avoid excessive strain. Fertility-friendly options include bodyweight movements like squats, lunges, and push-ups, as well as resistance band or free weight exercises such as bicep curls, shoulder presses, and rows. For those with access to equipment, leg presses, lat pulldowns, and lumbar extensions are also effective and safe when performed at low to moderate intensity. Pelvic floor exercises are especially valuable, as they strengthen muscles important for reproductive health and can ease delivery for those who become pregnant.

It’s important to avoid exercises that risk abdominal trauma, require lying flat on your back for long periods (especially after the first trimester), or involve heavy, jerky, or unbalanced movements. Supervised, individualized programs; ideally designed with input from a healthcare or fitness professional, help maximize benefits and minimize risks. When performed with proper technique and attention to your body’s signals, strength training can improve hormone balance, support healthy weight, and enhance overall well-being, all of which are linked to better fertility outcomes.

Strengthening the pelvic floor while you lift? Peek at Pelvic Floor Prep: Should You Do Kegels Before Pregnancy?.

How can you cycle-sync strength workouts with your hormones?

You can cycle-sync your strength workouts by aligning training intensity and frequency with the natural hormonal fluctuations of your menstrual cycle. Research shows that muscle strength and adaptation are often greatest during the follicular phase (the first half of your cycle, starting with menstruation and ending at ovulation), when estrogen levels are higher and recovery is enhanced.

During this phase, you may benefit from scheduling more frequent or intense strength sessions, as your body is primed for muscle growth and performance gains. In contrast, the luteal phase (after ovulation until your next period) is characterized by higher progesterone, which can affect energy, recovery, and perceived exertion; lighter or maintenance workouts may be more suitable during this time.

Some studies suggest that tailoring your training; doing more sessions or heavier lifts in the follicular phase and reducing intensity in the luteal phase, can lead to greater strength gains and better overall adaptation. However, individual responses vary, so it’s important to listen to your body and adjust as needed. This approach can help you optimize muscle building while respecting your hormonal rhythms and supporting reproductive health.

Learn the full month-by-month strategy inside Cycle-Smart Workouts: Best Exercises for Each Phase.

What special tweaks do PCOS, IVF, and male partners need?

For people with PCOS, strength training should be approached as part of a comprehensive lifestyle modification plan that includes both exercise and dietary changes. Moderate, regular strength training, such as two to three sessions per week, can improve insulin sensitivity, support weight loss, and help restore ovulation and menstrual regularity, which are often disrupted in PCOS. Circuit-style or interval-based workouts, combined with aerobic activity, have shown particular benefit, and even a modest weight loss of 5% can significantly improve fertility outcomes. It’s important to avoid extreme exercise or rapid weight loss, as these can worsen hormonal imbalances.

During IVF, exercise should be gentle and closely monitored. While moderate activity is generally safe, high-intensity or high-impact strength training is discouraged, as it may affect ovarian response or increase the risk of complications during ovarian stimulation. Instead, focus on low- to moderate-intensity resistance exercises, prioritize proper form, and avoid exercises that increase intra-abdominal pressure or risk trauma. Always consult with your fertility team before starting or continuing a strength program during IVF, as individual recommendations may vary based on your protocol and response. Full guide at Exercise During IVF.

For male partners, strength training can support fertility when performed at moderate intensity, as it helps maintain a healthy weight, improves metabolic health, and may support healthy testosterone levels. However, excessive or intense training—especially endurance sports or heavy, prolonged routines—can negatively impact semen quality, reducing sperm count, motility, and morphology. It’s best to avoid overtraining and ensure adequate rest and nutrition, as well as to steer clear of anabolic steroids or performance-enhancing drugs, which can severely impair fertility. Moderation and balance are key for optimizing male reproductive health. Cardio-inclined? Review Running While TTC: Safe Guidelines for Runners.

How should you fuel and recover so muscle gains don’t mess with hormones?

To fuel and recover in a way that supports muscle gains without disrupting hormone balance, it’s important to consume adequate calories, especially from carbohydrates and protein, after strength training. Research shows that post-exercise intake of a carbohydrate-protein combination stimulates insulin and growth hormone, both of which are crucial for muscle repair and growth, while also supporting healthy hormone levels.

Consuming protein before bedtime, particularly slow-digesting types like casein, can further boost growth hormone and IGF-1, aiding overnight recovery and muscle maintenance. Avoiding severe calorie restriction is key, as chronic under-fueling can lower anabolic hormones like testosterone and IGF-1, leading to muscle loss and hormonal imbalances. Gentle yoga or foam rolling on off days—see Yoga for Fertility: Five Poses to Relax and Conceive.

Recovery strategies should include not just nutrition but also adequate sleep and rest days, as these allow the body’s anabolic hormones to repair tissues and restore balance. Overtraining or insufficient recovery can blunt hormone responses and increase the risk of negative health effects. Track sleep, stress, and cycles via your smartwatch; tips in Wearable Fitness Guide.

In summary, prioritize balanced meals with enough protein and carbohydrates after workouts, avoid extreme diets, and ensure regular rest to maximize muscle gains while keeping hormones in a healthy range.

What does a sample week of fertility-friendly training look like?

In the two-week wait, downshift intensity with the routines in Two-Week Wait Workouts: Gentle Moves to Calm the Mind.

Your top questions, answered

Can I keep my CrossFit classes while TTC?
Yes, most evidence suggests that continuing CrossFit or similar strength training while trying to conceive (TTC) is generally safe for healthy, active individuals, as long as you adapt exercises to your fitness level and follow professional guidance. Avoid high-risk movements (like box jumps or heavy Olympic lifts) if you’re new to them, and always listen to your body.

Does lifting affect implantation?
There is no strong evidence that moderate strength training or lifting interferes with embryo implantation. In fact, maintaining regular, moderate exercise may support overall reproductive health, but it’s best to avoid extreme intensity or new, strenuous routines during the implantation window.

What if I miss a period after upping workouts?
Missing a period after increasing workout intensity or frequency can be a sign of overtraining or under-fueling, which may disrupt hormone balance and ovulation. If this happens, consider reducing exercise intensity, increasing calorie intake, and consult a healthcare provider to address potential underlying issues.

Is CrossFit riskier than other sports for injury while TTC?
CrossFit injury rates are similar to those of other recreational sports like weightlifting or running, but the risk can increase with poor technique, inadequate supervision, or sudden increases in intensity. Proper coaching and gradual progression help minimize injury risk.

Should I change my workouts if I get pregnant?
If you become pregnant, you may need to modify certain exercises, avoiding high-impact, supine, or Valsalva maneuvers as pregnancy progresses and always follow your healthcare provider’s advice for safe activity levels.

For more recovery ideas, hop over to Post-Workout Recovery: Tips for TTC Parents.

Final Thoughts

Strength training, when approached thoughtfully, can be a powerful ally for both muscle building and fertility. For women, supervised and individualized strength programs during preconception and pregnancy are linked to improved musculoskeletal health, better blood sugar control, reduced risk of gestational diabetes, and enhanced mental well-being, with minimal risks when performed safely and with professional guidance. For men, moderate resistance and combined aerobic training can significantly improve semen quality, hormonal balance, and pregnancy rates, while excessive or intense exercise may have the opposite effect.

The key across all groups is moderation, proper technique, and attention to recovery and nutrition, as overtraining or under-fueling can disrupt hormone balance and reproductive function. Ultimately, strength training is a valuable component of a fertility-supportive lifestyle, provided it is tailored to individual needs and life stages, and integrated with healthy habits and medical advice.

References

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2. Effectiveness of Exercise Training on Male Factor Infertility: A Systematic Review and Network Meta-analysis. Sports Health: A Multidisciplinary Approach, 14, 508 - 517. https://doi.org/10.1177/19417381211055399

3. The most common risk factors for infertility in men involved in competitive sports. Medical Science. https://doi.org/10.54905/disssi.v28i154.e157ms3487

4. Influence of physical activity on male fertility. Andrologia, 54. https://doi.org/10.1111/and.14433

5. The Influence of an Intense Training Regime in Professional and Non-Professional Athletes on Semen Parameters: A Systematic Review. Journal of Clinical Medicine, 14. https://doi.org/10.3390/jcm14010201

6. The Impact of Physical Activities on Male Fertility: A Systematic Review. Quality in Sport. https://doi.org/10.12775/qs.2025.38.58251

7. Hormonal changes in strength training during the menstrual cycle: a systematic review. Revista Brasileira de Fisiologia do Exercício. https://doi.org/10.33233/rbfex.v22i1.5373

8. Impact of BRACTS exercises on muscular strength in eumenorrheic women. Scientific Reports, 15. https://doi.org/10.1038/s41598-025-87352-6

Stellingwerff, T., Heikura, I., Meeusen, R., Bermon, S., Seiler, S., Mountjoy, M., & Burke, L. (2021). Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared Pathways, Symptoms and Complexities. Sports Medicine, 51, 2251 - 2280. https://doi.org/10.1007/s40279-021-01491-0 Wilk, M., Michalczyk, M., Gołaś, A., Krzysztofik, M., Maszczyk, A., & Zając, A. (2018). Endocrine responses following exhaustive strength exercise with and without the use of protein and protein-carbohydrate supplements. Biology of Sport, 35, 399 - 405. https://doi.org/10.5114/biolsport.2018.75754