An apparatus including an elongated apparatus structure configured to fit around a body part of a user and an actuator configured to change shape of the elongated apparatus structure. The actuator is configured to change tightness of the elongated apparatus structure around the body part of the user based on an action the apparatus is performing.
According to an example embodiment there is provided shaping and/or tightening of a wearable device with an actuator. The wearable device is for example a wrist band, a chest band, an ankle band or some other device comprising an elongated apparatus structure (e.g. a strap or a band) configured to fit around a body part or body extension of a user. The elongated apparatus structure is made of a suitable elastic, stretchable, flexible or bendable material (such as plastic, textile, or sheet metal), for example.
 For collection of data, e.g. heart rate, blood pressure or skin moisture, through sensors it is advantageous that the sensors are in contact with skin of the user. When the sensors do not collect data there is no need to have a skin contact, though. Use of the band is more pleasant to the user if the band is not at all times tightened around the user’s wrist or other body part. Therefore better user experience can be achieved by automatically loosening the band when the sensors end collection of data and by automatically tightening the band for the duration of the sensors collecting data.
The band may have many units like “microphones, displays, as well as additional circuitry such as a camera unit”.
 A skilled person appreciates that in addition to the elements shown in FIG. 6, the apparatus 600 may comprise other elements, such as microphones, displays, as well as additional circuitry such as a camera unit, further input/output (I/O) circuitries, memory chips, application-specific integrated circuits (ASIC), processing circuitry for specific purposes such as source coding/decoding circuitry, channel coding/decoding circuitry and ciphering/deciphering circuitry. Additionally, the apparatus 600 may comprise a disposable or rechargeable battery (not shown) for powering the apparatus if external power supply is not available.