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If your senses aren't stimulated, then your mind won't be stimulated, and you'll be headed toward nap mode. To help yourself stay alert, look for ways to stimulate your eyes, ears, and even your nose throughout the day. Try some of the following:  Keep your mouth engaged by sucking on a mint or chewing gum. Position yourself near a window that provides indirect sunlight. Sitting directly in the sun can make you tired, but being near sunlight can wake up your senses. Wake up your sense of smell by sniffing peppermint oil. You can carry a tiny bottle of it with you. Keep your eyes active by taking breaks to shift your gaze when they get tired from looking at the same thing. Listen to music. Jazz, hip-hop, or light rock can wake you up. Keeping your body stimulated is just as important as stimulating your senses. If your body is more alert, your mind will be too, so you should try to keep your body engaged no matter where you are. Try a few of these tricks:  Gently pull down on your earlobes. Pinch yourself in parts of your body that don't have much fat, such as your forearms or the space under your knees. Stretch your wrists by pulling your fingers back away from you. Roll your shoulders and your neck. If you really feel like you're in danger of falling asleep, lightly bite down on your tongue. While intense exercise might wear you out, light to moderate exercise will improve your overall energy level and make you feel invigorated. Take 15-30 minutes to exercise in the late morning or early afternoon, when you need an extra boost of energy.  Go for a brisk walk around the neighborhood. Nothing will wake you up like filling your lungs with fresh air. Take a midday yoga class. This is another great way to clear your mind, improve your breathing, and to get ready for the rest of the day. You’re engaging in moderate exercise if your heart rate is somewhat elevated and you’re breathing heavily enough that it’s tough to carry on a full conversation. Don’t do more than light exercise after mid-afternoon—if you work out late in the evening, your adrenaline will spike and it may be harder for you to fall asleep. Even if you don't have time for a full workout, you can make your body more alert by engaging in some basic physical activity throughout your day. Just a few minutes of physical activity from time to time is a great way to tell your body, "Hey, it's not time for sleep!"  During the workday, take short walks in the halls or go across the street to get coffee. Avoid elevators whenever you can. Take the stairs instead. If you're sitting at a desk all day, stand to do some basic stretches at least once per hour. A healthy breakfast is a great way to kick off your day, but you need to follow it up with a nutritious lunch and dinner as well. Eating healthy foods will give you more sustenance and energy, while unhealthy foods can drag you down and make you feel ready for bed.  Carry around an array of healthy snacks so you don't give in to the vending machine. Some great snack foods are almonds and cashews, celery sticks and peanut butter, and fresh or dried fruits. Eat three healthy and balanced meals throughout the day. Make room for some light snacking so you don't overindulge during mealtime. Avoid heavy meals, starchy foods, or foods that are high in fat or sugar. All of these foods will make you more tired and will tax your digestive system. Have some caffeine in the early afternoon, between your natural cortisol spikes at around midday and early evening. Stay hydrated throughout the day. Energy drinks often have at least double the amount of caffeine of a cup of coffee, and they frequently have excess sugar and various unregulated ingredients that may have unintended health consequences. It’s much safer to rely on getting enough sleep at night, eating healthy, and staying active during the day to avoid being tired. Energy drinks will give you a temporary boost of alertness, so consider using them sparingly and only when necessary. Energy drinks can cause heart and blood vessel problems in some people, so talk to your doctor before using them, especially if you have any cardiovascular issues. Never mix energy drinks with alcohol, as it can make you more likely to drink too much without immediately recognizing the effects.
Stimulate your senses to keep your mind active. Give your body mild stimulations to stay alert. Exercise in late morning or early afternoon for an alertness boost. Find ways to keep your body moving if you can’t exercise. Maintain a healthy diet throughout the day. Don’t rely on energy drinks to keep you going.