It's officially hot in Central Texas. Not as hot as last year, where Austin experienced 69 days of triple-digit heat, straining air conditioners and people's patience to the breaking point, but we're getting close to the first 100-degree day of the summer. High temperatures are not the only thing to keep an eye on this time of year. You also want to pay attention to the humidity level, as well as the heat index if you plan spending time outdoors and especially if you will be exercising.

Heat Index

Temperature only tells half the story. When factored with the relative humidity, the result is called the Heat Index, which describes how hot it feels outside. We were surprised to learn that there's only a few hours during the day that aren't under a cautionary flag.

The Heat Index is the one number you should listen for in weather reports more than any other if you are going to be outside and engaging in physical exertion whether for fun, exercise or work. If the numbers reach a dangerous level mid-morning and last throughout the evening, you may want to reschedule your physical activity to the earliest possible time in the morning.

If you look over the numbers below*, you'll see how early in the day the heat index climbs past 80 degrees. In addition, once the heat arrives for the day, it tends to stick around all afternoon and into the evening, usually not dissipating until early morning.

* The shaded values reflect degrees Farenheit. The heat index data was recorded and reported by Wunderground.com on August 5, 2006.Exposure to full sunshine can increase heat index values by up to 15 °F.

Heat Index	Danger Level	Symptoms
Above 130	Life threatening	Heatstroke possible with only brief activity
105 - 130	Extreme danger	Heat cramps, exhaustion, headaches after brief activity
90 - 105	Danger	Heat cramps, exhaustion, headaches after prolonged activity
80 - 90	Caution	Exercise causes fatigue more rapidly.
Below 80	No Danger	No precautions necessary.

Switching your physical activity to early morning can have additional benefits as well. Once the sun comes up on clear days, the Ultraviolet Index also rises, increasing the risk of sunburn and other ill effects of ultraviolet light. As the summer months fall within the Ozone Season, further benefits can be gained by exercising early before ozone levels reach alert status, causing respiratory irritation and inflammation in much of the population. Another choice is to change your outdoor workout for an indoor one.

Six Indoor Exercises That Beat the Heat

Squats

The number one thing to remember is to never allow your knees to move in front of the front of your toes. To get familiar with the movement, it's a good idea to step in front of a sofa or other low piece of furniture. Push your toes to the edge of the piece of furniture or even an inch underneath. It may feel weird but the next step is to extend your rear end outwards, which then gets your knees in the proper position. Then, lower your rear end until your quadriceps are 90-degrees to the floor. Don't feel you have to bend until 90-degrees. Work up to 90-degrees over time and add more repetitions over time.

First Try 10 squats x 3 sets. Work up to 25 repetitions.
Medium Level 25 squats x 3 sets. Work up to 50 repetitions.
Advanced Hold lightweight dumbbells in each hand and extend overhead while performing squats.

Side Plank

Lie on your back with your legs extended and your arms to your side. Roll over onto either side with your upper body weight positioned on your forearm and elbow and elevated at a 45-degree angle. One foot should be placed over the other and ankles should be side-to-side. Inhale and contract your abdominal and rear end muscles. Next, extend your hips upwards vertically toward the ceiling so that your spine is straight. Count to 10 and repeat for five repetitions. Be sure to breathe while you are counting. Turn over and repeat for the other side.

Medium Level Count to 20 and repeat for 10 repetitions.
Advanced Count to 30 and repeat for 15 repetitions.

Crunch

The crunch is the safe alternative to the sit-up. Lie flat on your back with your knees bent. Place your hands behind your neck or beside your ears or crossed over your chest. Be sure not to pull on the neck with your hands. Your neck should remain in a straight line with your spine at all times. Engage your core by mentally thinking of pulling your belly button toward the floor. Curl your shoulders toward your knees but only as far as your lower back does not leave the floor. You can perform this exercise on an exercise ball.

First Try 10 repetitions x 3 sets. Work up to 25 repetitions.
Medium Level 25 repetitions x 3 sets. Work up to 50 repetitions.
Advanced Increase resistance by holding light weights in each hand underneath the chin. 25 repetitions x 3 sets. Work up to 50 repetitions.

Burpee

The burpee is a funny name for a very good full body exercise. Many travelers are in favor of this exercise for its ability to activate so many muscles in the body without the need for a gym or accessories. If performed correctly, the burpee satisfies both as a strength and cardiovascular workout. Begin by standing with your arms to your side and your back straight and your feet about shoulder-width apart. Perform a squat and continue reaching for the floor until your hands touch the floor in front of your feet. Youll want your hands about six inches from the outside of the foot as this will provide more stability for the next part of the move. Place your weight on your hands and extend your feet back until you are in a pushup position. Lower your chest to the floor to perform the pushup and then back up. Bring your feet forward to their starting position. Your hands and arms should now transfer your weight to your feet. Look straight ahead and then leap from this position to straighten your body in one long extension of arms, trunk and legs into a line. You do not have to leap too far in the air. An inch or two is fine.

First Try 5 repetitions x 3 sets. Work up to 15 repetitions. If you cant perform a full pushup, place the knees on the floor to relieve some of the resistance.
Medium Level 10 repetitions x 3 sets. Work up to 20 repetitions.
Advanced 20 repetitions x 3 sets. Work up to 50 repetitions.

Pushup

There's a good reason the pushup has been included in so many training routines over the years. If your schedule is so limited you could only afford to perform one exercise, it would have to be the pushup. The exercise works the chest, shoulders, arms, back and abs all at the same time.

On the floor, get on your hands and knees and place your hands underneath your shoulders or just outside of the shoulders. Make sure your fingers are pointing forward. Work your feet back so that your body forms a straight line. You may look underneath to check how straight you are but then look forward before lowering your body until your arms are bent at 90 degrees. Push back up and repeat. Do as many as you can and then lower your body to the floor. Repeat for two more sets.

Calf Raises

You'll need to find a good step to perform this exercise. A step on some stairs, a curb or any platform difference of six-to-eight inches will work. The exercise works better if you're able to balance by holding onto something. To start, rest the balls of your feet on the step with your heels off the back and suspended in mid-air. Your body should be in a straight line from your ankles to your shoulders. It is ok for you to bend your knees slightly. Lower the heels of your feet several inches and then press against the balls of your feet to raise the heels above the level plane of your foot. Repeat for 20-30 times. Rest and then perform two-to-three sets. This exercise concentrates primarily on the calf muscles and muscles surrounding the ankle.