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Why is it a bad idea to do weight training after cardio training?

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Matthew 11:28-30

Cardio depletes the stored muscular glycogen that is used as fuel for weight training. This leads to less fuel for your weight workout.

Warming up for 5 - 10 minutes before lifting by doing low intensity cardio is OK, but a 30 minute cardio session at moderate intensity will compromise your weight workout

Good answer.

Furthermore, your body will start burning fat faster if you do cardio AFTER weights. This happens because weight training depletes the stored muscular glycogen, so when instead of burning that during cardio your body will burn fat.

At least that's what I read.

I've read that also.

However, if your weight workouts run an hour or more, following up immediately afterwards with cardio may be counterproductive. This is because long workouts stimulate the release of cortisol, a hormone which promotes muscle breakdown and fat storage.

Another option would be to do your cardio earlier or later the same day, with several hours in between. For example, you could do cardio in the morning and weight train in the evening, or vice versa. Or, you could just do cardio on days you don't lift weights.

Muscle and fitness had a study a while back that showed growth hormone levels at rest increased by 500% with a cardio-weights workout, but an "even more incredible" (that's close to their words) 1800% with a weights-cardio workout. I forget the details, but you may be able to find them on muscleandfitness.com.

After that, I feel embarrased to admit that I've violated the "weights before cardio" rule on numerous occasions. When I'm pressed for time, for example, rather than just blow off cardio at the end of the workout I'll do 15 mnutes of cardio at the beginning, blowing off the warmup. Even fairly intense cardio sessions that short won't really hurt my weight workouts that much if I keep them brief as well.

And for some people - endurance runners doing hill workouts, or boxers sparring - weight training afterwards makes sense

The takeaway - don't be afraid to think outside the box. It's better to do cardio after weights in most circumstances, but "most" doesn't mean "all." Mixing things up every now and then is good

"Guest" above is me

I think I can understand the logic with endurance runners, but I'm not sure I follow with boxers. Please explain.

80% of boxing is footwork and keeping your hands up. A weight workout with a lot of squats and/or arm work might make that difficult.

Although now that I think of it, bringing up boxers might be flawed logic - boxers are the last holdouts to weight training. There still is the feeling among many boxers that weights make you slow. That might be true if they use bodybuilding-type training. Explosive-type training - Olympic lifts and plyometrics - is probably better suited for them.

I think a lot of ring sports (boxing/kickboxing/UFC) would be a lot different if fighters were grouped into height classes instead of weight classes.

There would be some SERIOUS mismatches as a result of that. Fighters like Jeff Monson would completely dominate their height class.

You can get around that by drinking a carb source (ie Gatorade) during the workout. This is especially recommended if you are over 40, as people in this age group produce more cortisol in response to prolonged exercise.

Interesting ..... but wouldn't taking in carbs negate the fat burning aspect of cardio (at least durring the workout)?