Working out isn't just great for your waistline; if you do it early in the morning, it can be especially beneficial to your career, LinkedIn network and entrepreneurial bottom line.

I've been a morning gym rat for nearly 20 years -- the past 10 of them in the wee hours of 5 and 6 a.m. It's been key to my mental, physical and professional health. Here's how I have benefited from not hitting the snooze button (as much as I'd like, anyhow) and choosing instead to break a sweat before 6 a.m. It could be great for you, too, so upload that playlist and your favorite theme songs and get moving.

1. It's a super time to network.

The people you want to know who can help open doors for you professionally are the people who work out first thing. They don't have any other time to do it and they might not sleep that much anyhow. I've made great connections at the gym. I met my accountant in Pilates class. While on the elliptical machine, I said "yes" to a request to speak at someone's Rotary club meeting. Likewise, I've done my part, giving referrals before spin class, for example.

2. It's prime time for exercising the brain, too. 

Each morning, I walk out of the gym with at least one good idea that occurred to me while working out. Recently, I had an epiphany on a section of a presentation I've been working on and was messaging my client before I pulled out of the parking lot to go home. I've thought through strategies for my public relations clients. If nothing else, I've discovered a new song to motivate my next workout. 

3. It's an immune system booster. 

Regular exercise boosts your immune system. Guess what? That means you get to work more and be more productive. There are no guarantees you won't get a cold just before an important presentation, deadline or business trip, but at least you'll know you did what you could. I have two children, so I know I'd be sick a lot more often if not for my daily fitness routine. Don't believe me? Trust Harvard Medical School.

4. It sets you up to handle whatever the day throws at you.

This is my favorite reason of all. By exercising first thing in the morning, I've done something for myself that nothing and nobody can take away from me. Bring on the endless conference calls, the client emergencies, the school nurse phoning to say the kiddo is sick. I'm ready. I trained for you -- super early this morning.