The concept of fasted training, or working out on an empty stomach, has gained popularity in the fitness world for its potential benefits. However, when it comes to women, this approach may not always be the best choice, particularly when considering its potential impact on hormonal balance, including cortisol, the body’s stress hormone.
Understanding Fasted Training
Fasted training involves engaging in exercise when your body is in a state of low glycogen (an important source of energy that your body stores mainly in the liver and muscles), this typically happens in the morning after an overnight fast. Advocates argue that it can enhance fat utilisation and potentially improve metabolic adaptability. However, other factors come in to play that can affect results, specially for women.
The Role of Cortisol
Cortisol is a hormone produced by the adrenal glands in response to stress. It plays a crucial role in various bodily functions, including regulating metabolism, immune response, and blood pressure. Cortisol levels naturally fluctuate throughout the day, with higher levels in the morning to help wake you up and lower levels at night to promote sleep.
The Connection
When it comes to fasted training, cortisol levels can come into play in the following ways:
• Stress Response: Fasted training can be seen as a form of stress on the body, especially when performed intensively. In response to this stress, the body may release higher levels of cortisol. For women, this can potentially exacerbate the hormonal fluctuations already occurring throughout the menstrual cycle.
• Potential Overproduction: Training fasted during times of hormonal flux, such as the luteal phase of the menstrual cycle (after ovulation, when your body releases an egg), may lead to an overproduction of cortisol. Elevated cortisol levels can disrupt hormonal balance and potentially lead to irregular menstrual cycles or other hormonal imbalances.
These imbalances may present themselves as changes in skin/hair, irregular periods, loss of libido, muscle weakness and fatigue.
• Impact on Recovery: Cortisol has catabolic effects, meaning it can break down muscle tissue. Training fasted, particularly when cortisol levels are high, may counteract the muscle-building benefits of exercise and impair post-workout recovery.
3 points to consider:
For women, hormonal fluctuations are a significant aspect of their physiology. The menstrual cycle, in particular, has a profound impact on energy levels, mood, and physical performance.
I. Menstrual Cycle Phases: The menstrual cycle consists of several phases and begins the first day of your period. With two key stages being the follicular phase (before ovulation) and the luteal phase (after ovulation). During the luteal phase, which occurs in the second half of the menstrual cycle, the body’s metabolism tends to shift towards carbohydrate utilisation. Training fasted during this phase can lead to decreased workout intensity, as the body may struggle to access sufficient glycogen stores for energy. The week before your cycle is the time you need to make the hormone progesterone, so you’d want to focus on eating hormone building foods such as olive oil, avocado or nuts and avoiding ketosis (the metabolic state that occurs when your body burns fat for energy instead of glucose).
II. Hormonal Variability: Hormonal fluctuations throughout the menstrual cycle can influence energy levels, motivation, and mood. Women may find it challenging to maintain workout intensity and focus when training fasted during these fluctuations.
III. Muscle Preservation: For women looking to build or preserve muscle mass, fasted training may not be the most conducive approach. Consuming protein before a workout provides the essential amino acids necessary for muscle recovery and growth, which can be particularly vital during the luteal phase when muscle breakdown rates may increase.
Alternative Approaches for Women’s Fitness:
Considering the potential impact of fasted training on cortisol levels and hormonal balance, some alternative strategies for women to optimise their fitness routines are:
1. Pre-Workout Nutrition: Consuming a balanced meal or snack before a workout can provide essential carbohydrates and protein to enhance energy levels and muscle recovery.
2. Hydration and Electrolytes: Staying well-hydrated and maintaining proper electrolyte balance is essential for performance and overall well-being. Ensure you are hydrated before, during, and after your workouts.
3. Adaptive Nutrition: Adjust your nutrition to your menstrual cycle. During the luteal phase, consider incorporating slightly more carbohydrates to support energy needs. This can help offset the potential energy drain associated with hormonal changes.
4. Listening to Your Body: Pay close attention to how your body responds to fasted training and the potential signs of elevated stress, such as disrupted sleep patterns or mood swings. If you consistently experience these symptoms, consider adapting your routine to incorporate pre-workout nutrition.
If you haven’t already, we recommend using apps such as Clue or Flo to familiarise with your cycle and understand the different phases your body goes through.
It’s essential to remember that individual responses to hormonal changes and dietary adjustments can vary. Consulting with a healthcare professional or a qualified nutritionist who is familiar with your specific health needs and goals is advisable for personalised advice and guidance. Additionally, scientific research on the relationship between menstrual cycles, nutrition, and exercise is an evolving field, and individual factors should be taken into account.