Arnold says if you have 1 hour a day to spare, you can work out.

You don't even need an hour. Try 5 minutes of Dan John's ABCs with 2 kettlebells. You'll want to look it up, but an ABC is 2 cleans, one overhead press, and 3 squats. Bam, full-body workout.

Don't want to pay $20-50 for 2 kettlebells? 5 minutes of burpees with a squat at the bottom, no equipment required.

Everyone has the time - it's the effort that they don't want to go through. It's also easy for me and fitness people to be condescending about that, which turns people off, so I always start with the 5 minute time. Just give yourself 5 minutes of feeling like hell. It'll be over soon and then you can reflect on what just happened and if you have the energy to keep that up regularly.

By the way, effort is more important than raw numbers. No matter how you're feeling or how tired you are, give a hard effort relative to THAT.