Sure...but probably because I live in a small city which there is not real motivation to have the "extra" energy as I do back home. 

It could be your diet. If you're eating a lot of fried foods, or rice, or noodle dishes... I'm guessing they use mostly rice flour for their noodles and baked goods, instead of wheat flour. 

I'm also guessing the air isn't conducive to exercising, especially if you're lungs aren't used to all the pollution. And if you aren't exercising, that makes you more lethargic. You have to force yourself to do it. If you can get out of the city on the weekend and go for a hike or walk or run in the country side, that would be better. 

If you've seet up an air purifier in your apartment, try some low impact aerobics and light weight training to build up muscle.

Once you start and get back into the swing of it, it'll get easier. I know it took me a while to do after I was sick. It isn't easy. It's a vicious circle. A mix of lack of exercise and a poor diet, makes you feel lethargic, and that can lead to depression, which makes you less willing to exercise and eat healthy.  You have to force it though. Start small so it isnt overwhelming and you aren't setting yourself up for failure. 

I'm entirely lethargic and lazy. I think, for my side, there's probably a few reasons, but the most important one is that my work really drains me and I haven't taken a holiday in more than half a year, so that definitely contributes in a major way to being run down.

Also, sometimes leaving the house is such a hassle; small things can become big problems. 

China has pretty much defeated me.

I feel the same.  I blame it on the uncomfortable beds (improper sleep means I'm never well-rested).  That, and a lack of motivation to go outside due to the inability to communicate, with poor air quality and a lack of gyms.

I'm the opposite, I felt lazier in North America. When i first moved here and I began to eat rice and noodles for breakfast and lunch, I did begin to feel a lack of energy, after that I changed my diet around and stayed clear from rice and noodles, still eating Chinese food, just less carbs

Lethargic, definitely. The one thing that keeps me here is the knowledge that this stint in China will pay for an entire year of travel and so much more. With the cost of living back home I'd find it impossible to save so much per month. Also, I think I'd be much more energised if I was actually seeing some of the country I work in, not just doing the daily grind -- on my days off I just want to catch up on sleep, do laundry and drink.

bit of both really. On the weekend and if its polluted I tend to do nothing as I rather be indoors than outside. If it is a sunny weekend I'm like a cat on heat.

Now that you mention it I do spend less time being active outside. I blame the dust in the air, the air polution, and a lack of physical activities that I enjoy.

Physically, I'm more lethargic. I think it's a combination of the less than healthy food and hard bed. However, for my music, I have been feeling more motivated. At least it makes me feel like I accomplished something.

        Ooh...non!!!   On the contrary:  here I feel more active than in my home country.

In matters of eat,   I still eating relative de same, or less carbohidrate, once here I can afford to care more better to my diet uses.......

yes..i have squeezed my life to myself only..social activity is nothing here ..i can say my life revolve around me me and me only..

It motivates to the point of breaking even. If I was a dog I'd go woof woof all the way home! But you know what it's motivating where I stay!

I don't know about China motivating me, but having a two year old daughter and having looked into the cost of kindergarten education is CERTAINLY motivating me! That stuff aint cheap!

I got off my ass and walked more because I like to look. At home I don't walk enough and I live on a nice quiet road that runs along the water and I have a Collie that likes walks.

 As for doing other things, I like building, repairing. I have bikes and cars at home. In China I have no tools. I like cooking, but in China I have no real kitchen or food ingredients that I want. So China stifles me. I love the heat tho, tired of being cold and short summers, and too many pains when it gets cold.

Same as Ted above, Just i do not ha colie and i got some tools, for home repairs. every "friends" here are wondered, how can i use the screwdriver or drill. some of them do not buy Ikea products, and if they do, so asking the staff to come and set up few things in value of few hundreds, when the service is likely 70-150rmb for 10 screws .

what motivation i can get here ? 

I was very lazy and worked at home.........  here I am very lazy and don't work ...this is far better!!!!!!!!!!