Stress can come in many forms—there's emotional stress brought on by relationships or work, and then there's physical stress caused by exercise (the benefits of which come from adapting to that stress).
In stressful situations, the body increases the release of stress hormones like cortisol, which research shows can have a negative impact on your strength and muscle-mass gains. So, what can you do to help combat it? Sipping green or black tea and taking fish oil may result in a reduction in anxiety levels. Also, consider adding yogurt to your diet; the naturally occurring probiotics may help reduce stress levels.
When it comes to lifestyle changes, consider yoga and meditation.