The sequence by which Bach, Mozart, or no music were administered (over 3 consecutive days) was determined by randomization using random numbers. Infants listened to Bach or Mozart using the compact discs entitled "Baby Bach" and "Baby Mozart" (Baby smart, Nir Zvi, Israel). The music was played using a music player at a volume of 65-70 dB with attached speakers which were placed at a distance of 30 cm from the infant's ears. According to the American Academy of Pediatrics recommendations (5): the volume did not exceed 75dB and the background noise near the infant's ears was maintained below 45 dB. Music (Mozart or Bach) was initiated 10 minutes prior to the beginning of the metabolic measurements and continued for 30 minutes while energy expenditure (EE) was recorded. In the same manner EE was recorded for each infant with no music therapy.

The sequence by which Bach, Mozart, or no music were administered (over 3 consecutive days) was determined by randomization using random numbers. Infants listened to Bach or Mozart using the compact discs entitled "Baby Bach" and "Baby Mozart" (Baby smart, Nir Zvi, Israel). The music was played using a music player at a volume of 65-70 dB with attached speakers which were placed at a distance of 30 cm from the infant's ears. According to the American Academy of Pediatrics recommendations (5): the volume did not exceed 75dB and the background noise near the infant's ears was maintained below 45 dB. Music (Mozart or Bach) was initiated 10 minutes prior to the beginning of the metabolic measurements and continued for 30 minutes while energy expenditure (EE) was recorded. In the same manner EE was recorded for each infant with no music therapy.

Infants listened to Bach or Mozart using the compact discs entitled "Baby Bach" and "Baby Mozart" (Baby smart, Nir Zvi, Israel).

Metabolic measurements were performed by indirect calorimetry using the Deltatrac II Metabolic monitor (DateOhmeda, Helsinki, Finland). This system consists of a hood, which is placed over the infant's head and of two sensors. It uses the principle of an open circuit which allows for continuous measurements of O2 consumption and C02 production. The energy expenditure is calculated using the equation 5.5VO2+1.76VCO2.