A method and apparatus for measuring a first bio-signal from a user in an unrestrictive manner are provided. The method includes extracting a second bio-signal including a motion signal and a respiration signal, based on the first bio-signal; determining an apnea measurement reference signal including a respiration measurement signal and a motion measurement signal, based on the second bio-signal; dividing the apnea measurement reference signal by a first time interval to generate a first evaluation signal, and dividing the first evaluation signal by a second time interval, that is smaller than the first time interval, to generate second evaluation signals; calculating standard deviation information based on the second evaluation signals; and determining a sleeping pattern for the second time intervals corresponding to the second evaluation signals, based on the standard deviation information.