If, in response to a life event, you’ve ever felt heat in the face, tightness in the chest, deep fatigue, an upset stomach or a craving for junk food, you know what stress feels like in your body. Chances are you’re well aware that stress can lead to elevated blood pressure, stroke, heart attack and weight gain.

But did you know that stress also contributes to mental health challenges such as anxiety, depression or an overall sense of defeatism? In order to stay mentally fit at work and at home, we need to protect ourselves against harm.

But what exactly is stress? Basically, our brains perceive a stressful situation as a threat. We respond to threats in our environment (a saber-tooth tiger or a last-minute presentation to a big client) by increasing our ability to perform physically and mentally (run and think faster). We do this by releasing the hormones epinephrine (also known as adrenaline) and cortisol into our blood.

The benefit of adrenaline and cortisol is that they increase our capacity to function at a high level, both mentally and physically. This is a good thing in short bursts. But if those hormones are dumped into our bloodstream day after day, they cause problems.

Here is a fact to hold in mind at all times:

Short bursts of stress (called acute) are essential for helping us to perform at a higher level. But elevated stress over long periods of time (called chronic) can make us sick.

Gearing up for a big presentation is a time of acute stress that can boost your performance. Being stuck in a job you hate is the sort of chronic stress situation that is the real mental health killer.

The key to managing stress is to introduce regular recovery periods into your life. Try these seven techniques to build your mental and emotional fitness.

1. Eat healthy.

Your emotions ask for comfort foods in times of stress, but your mind and body really need healthy, nutrient-dense foods to help cope with, and recover from, stress. This is the time to load up on fresh meats, fish, vegetables and fruits and complex carbs.

Related: 12 Ways to Eat Healthy No Matter How Busy You Are

2. Exercise equals endorphins.

Exercise releases endorphins that cause deep feelings of wellbeing and, sometimes, even euphoria. Think of runner’s high. Daily exercise is a powerful way to build mental fitness. Amplify this experience by working out with a friend.

3. Introduce 'muscular meditation' into your day.

Muscular meditation is any activity where you move in a repetitive, rhythmic pattern. Examples include walking, swimming, cycling, jogging, rowing and paddling. This form of movement puts the brain in a relaxed state and decreases symptoms of depression and anxiety. Tips: go for at least 15 minutes, take it easy and get out into nature if possible.

4. Schedule distraction-free times.

Try to spend an hour each day away from electronic devices and responsibilities. Do anything you especially enjoy: meditate, listen to music, get out to the park, read, take a bath. This is relax-and-unwind time.

Related: This Man Made His Smartphone 'Distraction-Free' -- And It Changed His Life

5. Practice cognitive reframing.

This refers to changing your beliefs about events, which can actually change the physical structure of your brain. Basically, an event is only negative if you perceive it to be so. If you reframe an event as a difficult (or even welcome) challenge to overcome, your stress lessens. Ask yourself, is there an upside here? Can I make this into a positive event? Challenge your own assumptions about how you view things, reframe the event, and focus on the growth opportunity.

6. Practice daily gratitude.

Science now backs up the idea that practicing daily gratitude for the things you appreciate helps you recognize the good parts of life, increases your overall happiness and lowers stress.

7. Spend time on relationships.

Good relationships lower stress. Invest some time each week on strengthening bonds with family and friends. Make a phone call to catch up with someone, go to the park with your kids, take your spouse out for dinner, or do a workout with a friend.

You’re not a rudderless vessel tossed on the Sea of Stress. You have twin engines: your mind and body. You can propel yourself in any direction during times of stress until you reach firm ground. Choose how to perceive stressful situations and take action to improve your mind fitness.

Related: 25 Tips for Having Meaningful Relationships