Is it okay to use std::this_thread* functions from boost::threads?

Is it okay to mix and match things from boost::thread and std::thread, or should one set of functions be used for each?

I ask because my code uses boost::threads, but I've found that boost::this_thread::sleep_for doesn't behave properly when setting the system time back, but std::this_thread::sleep_for does, so I'd like to change my sleep function call and avoid changing all my boost::threads to std::threads if possible.