An In-Lab Sleep Study (also known as a PSG) is conducted overnight at a sleep clinic or hospital where clinical staff will place sensors on your body to monitor your sleep, record brain activity, eye movements, heart rate, and blood pressure. A In-Lab Sleep Study also records the amount of oxygen in your blood, air movement, snoring and chest movements. The chest movements show if you are making an effort to breathe. In-Lab Sleep Studies often are done at sleep centers or sleep labs.