Midlife Metabolism: Resetting Your Health in Your 40s
Your 40s can feel like a turning point in your health. Many women notice changes that seem to come out of nowhere:
Fatigue that doesn’t lift, no matter how much you rest.
Overheating at random times of the day.
Stubborn weight gain, especially around the middle, despite eating well and exercising.
Trouble falling or staying asleep.
Irritability and mood swings that leave you feeling snappy.
It’s frustrating, confusing, and often dismissed.
What’s Really Going On?
Hormonal changes are at the heart of these issues. In your 40s, key hormones—thyroid, cortisol, insulin, and reproductive hormones—start to shift. These shifts disrupt the delicate balance that kept you feeling stable in your 20s and 30s.
Perimenopause: The Starting Point
Perimenopause can begin as early as your late 30s or early 40s. Your ovaries may release a follicle but not an egg, leading to erratic estrogen and progesterone levels. This sets off symptoms like:
Hot flushes and night sweats
Sleeplessness
Irritability
Vaginal dryness
Low libido
Brain fog
Low motivation and energy
These symptoms are often brushed off as normal, but they’re signals of deeper changes in your body.
Cortisol and Insulin: The Stress-Weight Connection
When estrogen declines, cortisol (your stress hormone) rises. High cortisol levels can lead to increased insulin, making your body more likely to store fat—especially around your middle. Add in sugar cravings and high-carb snacks, and the cycle reinforces itself.
Thyroid: The Metabolic Regulator
The thyroid controls your metabolism, energy, mood, and body temperature. As its function slows, you might notice:
Weight gain
Fatigue
Feeling cold or overheated
Low mood and stress intolerance
Together, these hormonal shifts can feel like a cascade—one domino falls, and the rest follow.
What Can You Do About It?
Rebalance Your Hormones
Here’s the good news: You don’t have to feel stuck in this hormonal rollercoaster. By targeting the root causes of your symptoms, you can restore balance.
Support Ovulation
Naturopath and author, Lara Briden emphasises the importance of ovulation—even in your 40s. Eating enough protein, managing stress, and ensuring you’re not under-eating are key. These strategies help stabilise estrogen and progesterone.Prioritise Strength Training
Dr Stacy Sims’ research highlights the importance of resistance training for women over 40. Building muscle not only boosts metabolism but also improves insulin sensitivity and supports bone health. Aim for strength sessions 2-3 times a week and lift heavy.Reset Metabolic Flexibility
Reducing insulin spikes is critical. Focus on:High-protein, low-carb meals in the morning.
Healthy fats to support satiety.
Avoiding long fasting windows, as women over 40 are more sensitive to stress-related hormonal disruptions.
Adapt Your Exercise Routine
Cardio is not enough. Sims recommends combining strength training with short, high-intensity interval training (HIIT) sessions to improve metabolic health without overloading your cortisol.Test, Don’t Guess
Comprehensive testing—thyroid function, cortisol levels, insulin resistance, and sex hormones—can pinpoint what’s out of balance. Use this data to create a targeted health plan.
The Bottom Line
You’re not imagining these changes, and they’re not inevitable. With the right strategies, you can navigate this hormonal transition with energy, stability, and confidence.
Don’t let your hormones take the driver’s seat—start reclaiming your health today.
