Dumbbells typically come in the form of a short bar with a weight on each end. Some are one-piece molded plastic (usuallly neoprene). Others have discs that can be swapped out, added to and so forth. The integrated style have the advantage of being low-cost, very sturdy and relatively safe to use. But you’ll often want several pair of different weights, offsetting the savings. Adjustable free weights allow you to choose how much weight you want to work with, but require a little time and sometimes a tool to make the swap.

Both offer an excellent range of motion that can be approached by very few weight machines. They allow you to move the mass any way you want so you can tailor your workout. It’s difficult to find a machine that will allow you to do curls, wrist work, deltoid development and more. When you can, it requires having more than one station on a weight machine, which increases its cost.

But, dumbbells can be a little riskier to use. While caution is required with weight machines, too, they make it less likely to slip and hit yourself with the weight. A weight machine offers a stack that slides up or down a fixed pole or an in-built resistance mechanism and it’s practically impossible to topple them over.

If you curl a free weight fast and hit yourself in the chest, you won’t be the first one to get a bruise that way. Many a foot has experienced the force of a dropped dumbbell, too. Getting ones made of neoprene helps only slightly, since 20 lbs dropped on your toe hurts whether it’s made of metal or not and the material is not spongy.

Free weights, since they’re quite a bit smaller than even the smallest weight machine, provide the ultimate in space savings. A weight machine will take up about as much space in a room as a treadmill, sometimes more if it has multiple stations. Dumbbells can easily fit under the bed or in the closet.

They’re also very flexible. Many models allow the weights to be attached to a barbell, which increases the value of your investment. Just remove them and slide them onto a bar that may be up to several feet wide and you can have an entirely different kind of workout.

Weight machines offer a different kind of flexibility, though, one that can particularly benefit the novice. With a weight machine it’s very easy to design a workout that is tailored to very specific muscle groups. Free weights make it a little more difficult to control the movement to hone in on just the ones you want.

If you’re on a strict budget, it’s best to start with a small set of dumbbells. Non-interchangeable plastic models sell for only a few dollars, but even a set that can be loaded up to 50 lbs or more can be had for a few hundred. A discount weight machine will start at that price and go up from there.

Also, if you want the most flexible workout possible, free weights are the way to go. Weight machines have some terrific benefits but dumbbells provide the greatest possible range of motion for the most varied workouts.

By performing warm-up routines, you actually do literally just that – warm up the body. Internal body temperature can’t raise by a large amount, or you would have all the symptoms of a fever. Nevertheless, the temperature in the muscles can, and should, be raised slightly in order to dilate blood vessels and loosen muscles.

That dilation leads to greater blood flow, which helps oxygenate muscles and remove the waste products of cellular activity. Warm muscles are looser, more supple and flexible. That reduces stiffness and lowers resistance to larger movements. That helps reduce the risk of injury and prepares the body for high-performance activity.

A good warm-up also raises the heart rate, respiratory capacity and the overall metabolic level. Among other benefits, this helps deliver nutrients to muscles that will be useful for the workout to come. Warm-ups help lubricate joints, too, as well as lowering the risk to stretched tendons and tears.

No matter what kind of sport or workout you favor, having a well-functioning cardiovascular system and supple joints and muscles are essential for peak performance and low risk of injury.

A 10-15 minute warm-up period, including static and dynamic stretching activities, should be a low-intensity version of the routines that will be undertaken when the warm-up is complete.

Focus the non-stretching aspect of your warm-up more on the specific types of movement called for by the sport or activity you plan to engage in. If you plan to jog five miles, take a brisk walk, followed by a few gentle laps of a hundred yards or less. If you plan to play tennis or golf, spend a few minutes on low-speed, low-impact swings.

As you progress through the warm-up, gradually increase the speed and range of movement. This helps prepare the body and mind both.

Making the increase gradual helps increase the cardio and lung systems, and slowly cranks up needed body chemicals systems without depleting them. It helps gear up the mind for a high performance routine or sports event, in a way that static or even dynamic stretches won’t.

Like any physical activity, don’t overdo it. Don’t warm-up too much or too fast. The idea is to prepare the body for a workout, not perform one.

At the end, you’ll be ready to perform the sport or workout of your choice at peak level with minimal risk of injury.

Why?

Humans take in and use water for a number of important physiological functions. It provides a medium for cells and tissues. It makes possible the transport throughout the body of important elements or compounds like sodium and sugar not to mention forming part of the blood that moves them. It provides structural cohesion and lubrication between all parts. But there’s one more highly important function it helps perform: temperature control.

Homeostasis is the body’s ability to keep certain processes and factors in equilibrium, this is not too far from a central point. Body temperature is one key item among those. When body temperature gets too high, we experience fever and ultimately heat stroke. If it’s too low, we get chills. Both are signs that the body is in a less than ideal state.

One major reason is that all chemical reactions within the body have to take place within a very narrow range in terms of rate. Compounds have to be used and produced at just the right quantities within a certain time in order to proceed properly, or at all. Temperature, for very basic physical chemistry reasons, is a key factor in controlling that rate.

So how does sweat play a role in that?

Perspiring does not occur primarily in order to keep the amount of fluid in homeostasis – urination does that, along with breathing (though sweating plays a small part). But it has a huge effect on body temperature. As we exercise, chemical reactions speed up and mechanical motion is taking place. Both those produce more heat energy, which raises the internal temperature.

But the body is constantly seeking homeostasis – an equilibrium within a narrow range around a central point. For humans, that’s 98.6F/37C on average – a small deviation is within normal range. As we sweat, the excess heat energy is moved from inside the body to the outside, along the surface of the skin, carried along with the perspiration.

Outside the body a physical principle is at work – Newton’s Law of Cooling. Inside too, but never mind for now. Ignoring advanced mathematics, it says essentially that warmer bodies lose heat to cooler ones. We get cooler, the air gets a little warmer. Air molecules collide with the sweat molecules and pick up some of the heat energy they contain. That lowers the temperature of the sweat, lowering our temperature in the process (on the outside).

The net effect is to take excess heat on the inside and move it to the outside, somewhat like a home air conditioner or a car radiator. That helps keep the internal temperature at a constant 98.6F/37C.

That process takes place with breathing and just simple exposure. But sweating makes the process much more efficient, since water can carry a lot more heat than air does alone.

So, though it may have its unpleasant aspects, be thankful you perspire. After all, if you lacked sweat glands like your dog does, you’d look very silly panting.