If you're on birth control, the advice about "training with your cycle" doesn't quite fit. Your hormonal pattern isn't the same as a regular cycle, and that changes everything.
Here's what's actually happening when you're on hormonal contraception, and how to adjust your training accordingly.
First: Understanding the Hormones
Before we talk about birth control, let's cover what these hormones actually do.
Estrogen
In a natural cycle, estrogen rises in the first half of your cycle and peaks around ovulation. It improves blood flow, enhances neuromuscular coordination, supports bone health, and helps with recovery. When estrogen is high, many runners feel strong and fast. It also affects ligament elasticity (which can increase injury risk during peak levels) and helps regulate body temperature.
Progesteron
This rises after ovulation and dominates the second half of your cycle. Progesterone increases core body temperature (making you feel warmer during runs), can increase resting heart rate, affects how your body uses fuel (favoring fat over carbs), and can make recovery slower. It's also responsible for many premenstrual symptoms.
Progestin
This is the synthetic version of progesterone used in birth control. While it mimics some of progesterone's effects, it's not identical. Different types of progestins have different properties, which is why one birth control pill might affect you differently than another. Progestins generally suppress ovulation, thicken cervical mucus, and can have varying effects on temperature, mood, energy, and athletic performance.
When you're not on birth control, these hormones rise and fall in a predictable pattern (given that you are not dealing with an underlying disease). When you are on birth control, that pattern changes or disappears entirely.
Not All Birth Control Works the Same Way
The type of birth control you're on determines how your hormones behave, and therefore, how your body responds to training.
Combined oral contraceptives (estrogen + progestin):
These suppress your natural cycle entirely. No ovulation, no natural hormone peaks. Instead, you get a steady dose of synthetic hormones for three weeks, then a hormone-free week (your "period" week, though this isn't a true period, just withdrawal bleeding).
Progestin-only pills (the mini-pill):
Lower, steady dose of synthetic progesterone. Some people still ovulate; others don't. Bleeding patterns vary widely.
IUDs (hormonal):
Release progestin locally. Hormonal impact is lower than pills, but still present. Many people stop having periods altogether.
Implants and injections:
Steady release of progestin over weeks or months. Often suppress ovulation and menstruation.
IUDs (copper, non-hormonal):
No synthetic hormones, your natural cycle continues, so the original guide applies to you.
Bottom line: If you're on hormonal BC, you're not cycling through estrogen and progesterone the way a runner that is not on BC does. That means the performance effects are different too.
What Changes When You're on Hormonal Birth Control
Research on athletes and birth control is still catching up, but here's what we know so far:
Temperature regulation:
Synthetic progestins can keep your core temperature slightly elevated throughout the month (similar to the luteal phase in a natural cycle). This means you might feel warmer during runs more consistently, not just in one phase.
Heart rate:
Some runners notice a slightly elevated resting heart rate on BC, though this varies by type and individual response.
Recovery and adaptation:
There's mixed evidence here. Some studies suggest combined BC may slightly blunt training adaptations (like muscle growth and VO₂ max improvements), while others show no significant difference. Progestin-only methods seem to have less impact.
Ligament laxity:
Without the natural estrogen peak at ovulation, you may have more stable ligament tension, potentially reducing injury risk compared to naturally cycling athletes.
Energy and fueling:
Synthetic hormones can affect how your body uses carbs and fats for fuel, though the effect varies widely. Some runners feel no difference; others notice they need to fuel differently than they did pre-BC.
Perceived effort:
This is highly individual. Some runners feel more consistent. Others feel like every run is harder. Your experience is valid either way.
Training Adjustments for Runners on BC
If you're on combined pills (21 active days + 7 placebo):
You'll likely feel most consistent during the three weeks you're taking active pills. The fourth week, when hormones drop, can feel similar to the late luteal phase in a natural cycle: more fatigue, slower recovery, heavier legs.
Training approach: Schedule harder efforts during active pill weeks if possible. Expect the placebo week to feel tougher and plan easier runs or a deload. Track how you feel across a few months to find your pattern.
If you're on progestin-only methods (mini-pill, IUD, implant, injection):
You might not have a predictable pattern at all. Some months feel great, others don't, and it's not always tied to a specific week.
Training approach: Use RPE* and how you feel day-to-day, not a cycle-based plan. Be flexible with workout scheduling. Focus on long-term trends, not week-to-week fluctuations.
If you skip placebo weeks (continuous pill use):
No hormone drop, no withdrawal bleed, potentially the most consistent performance month-to-month.
Training approach: You may be able to train more predictably than naturally cycling runners. Pay attention to cumulative fatigue over months, not weeks. Don't assume consistency means you can skip rest; you still need recovery.
The Heat Problem
One of the most common complaints from runners on BC: feeling hot.
If synthetic progestins are keeping your core temp elevated, you're essentially running in "luteal phase mode" all the time. That means you'll sweat earlier, runs feel harder in warm weather, and hydration becomes even more critical.
What helps: Pre-cool before summer runs (cold water, ice packs, cool showers). Run earlier or later to avoid peak heat. Don't dismiss how you feel; if it's hot, it's hot.
Should You Change Your Birth Control Based on Running?
That's a personal decision, and there's no one-size-fits-all answer.
Some elite athletes experiment with timing BC around competition schedules or switching methods to optimize performance. But for most runners, the benefits of effective contraception outweigh minor performance differences.
If you're struggling with side effects that hurt your training (persistent fatigue, terrible runs, weight gain, mood changes) talk to your doctor. There are many BC options, and what works for one person might not work for you.
What Matters Most
Whether you're on the pill, have an IUD, or use another method, the key is knowing your body's response.
Track how you feel. Notice patterns (or the lack of them). Adjust your training based on what you're experiencing, not what a four-phase chart says you should be experiencing.
Birth control changes your hormonal landscape, but it doesn't erase your ability to train smart, recover well, and get faster.
You just need a different map.
One thing to try: Keep a simple training log that includes how you felt (energy, effort, sleep, mood) alongside your workouts. After a month or two, you'll start to see whether your BC creates a pattern, or if your training needs to be more responsive day-to-day.
RPE = Rate of Perceived Exertion. This is how hard a run feels to you, regardless of pace or heart rate. It's usually rated on a scale of 1-10, where 1 is effortless and 10 is maximum effort. RPE is especially useful when hormones affect how your body responds to training—a pace that feels easy one week might feel hard the next, even though your fitness hasn't changed.
Dr. Sulin B
Disclaimer: The information provided in this newsletter is for educational purposes only and is not intended as medical advice. Always consult with your healthcare provider before making changes to your training, nutrition, or health routine.