Jet lag, medically referred to as desynchronosis, is a physiological condition which results from alterations to the body's circadian rhythms resulting from rapid long-distance transmeridian (east–west or west–east) travel on a jet airplane. It is classified as one of the circadian rhythm sleep disorders.

The condition of jet lag may last several days until one is fully adjusted to the new time zone, and a recovery rate of one day per time zone crossed is a suggested guideline. The issue of jet lag is especially pronounced for airline pilots, crew, and frequent travelers. Airlines have regulations aimed at combating pilot fatigue caused by jet lag.

Jet lag is a chronobiological-related problem, similar to issues often induced by shift work. When traveling across a number of time zones, the body clock will be out of synchronization with the destination time, as it experiences daylight and darkness contrary to the rhythms to which it has grown accustomed: the body's natural pattern is upset, as the rhythms that dictate times for eating, sleeping, hormone regulation and body temperature variations no longer correspond to the environment nor to each other in some cases. To the degree that the body cannot immediately realign these rhythms, it is jet lagged.

Natasha Anne Bedingfield (born 26 November 1981) is a British pop singer and songwriter. Bedingfield debuted in the 1990s as a member of the Christian dance/electronic group The DNA Algorithm with her siblings Daniel Bedingfield and Nikola Rachelle. Throughout the 1990s and early 2000s, Bedingfield recorded rock and gospel songs for the Hillsong London Church, while Daniel went on to enjoy success with hits "Gotta Get Thru This" and "If You're Not the One".

Bedingfield released her first album, Unwritten, in 2004. The album contained primarily up-tempo pop songs and was influenced by R&B music; it enjoyed international success with more than 2.3 million copies sold worldwide and she received a Grammy Award nomination for "Best Female Pop Vocal Performance" for the title track "Unwritten". Bedingfield's second album, N.B. (2007), was less successful but yielded the UK top 10 singles "I Wanna Have Your Babies" and "Soulmate". N.B. was not released in North America, but six tracks from it were included with seven new ones and released in 2008 as her third studio album Pocketful of Sunshine, with the singles "Love Like This" and "Pocketful of Sunshine" earning success on the charts. In December 2010, Bedingfield released her third album in North America named Strip Me.