As citizens of the information age, humans leave digital traces of behavior in their communication and movement patterns through our cell phone. The Global Positioning System (GPS) technology tracks the way persons commute to school or work or when visiting family and friends. Circadian rhythmicity describes the concept that many of the bodily functions follow a roughly 24-hour rhythm. Usually, the ability to do concentrated and focused work is best during daytime while humans rest and sleep during nighttime. The current study wishes to look for a relationship between patterns in participants' cell phone use (Android only at this point) and several of their bodily functions.

Cell phones with internet access (so-called smartphones) represent a rich source for user activity data. Each time one places a call, sends a text message, or uses an app, a data trace is being produced which overall reflects the user's social activity and behavior. This data is called 'social sensing data'. Researchers connected this type of data to the health status of the person operating the cell phone. An example is that an outbreak of seasonal flu may lead to fewer calls and text messages among cell phone users. Thus, the social sensing data may show for example how severe an outbreak is and how fast it is spreading.

"Circadian rhythmicity" describes the concept that many of the bodily functions follow a roughly 24-hour rhythm. Usually, the ability to do concentrated and focused work is best during daytime while rest and sleep occurs during nighttime. A disturbance of this pattern, for example by regular nightshift work, may lead to an increased disease risk, such as for the cardiovascular system, the heart and blood vessels. Natural factors within a body produce our 24-hour rhythm. This rhythm is affected by outside cues such as sunlight. Jet lag is a short-term form of a disturbed 24-hour rhythm. When a person travels fast through several time zones, by plane for example from the East to the West Coast of the US, s/he arrives with a time difference of 3 hours. Upon arrival, the body runs still at East Coast time, but is exposed to the environmental cues following the West Coast time, which may make the person feel groggy and disoriented at first. Within a couple of days the body time usually adjusts and the complaints discontinue.

The current study wishes to look for a relationship between patterns in the participant's cell phone use (Android only at this point) and several of the bodily functions. As bodily functions the investigators will measure blood pressure and breakdown products (metabolites) in urine, blood and saliva samples. The investigators will collect stool samples and use swabs to collect the microbes inhabiting the mouth as well as the rectum. The investigators will also measure messenger ribonucleic acid (mRNA), messenger products of the participant's heritable information, in the blood. A cell phone application called "Ginger.io" will collect the participants' cell phone usage information. This application will also ask the participant several questions during the installation, during participation as well as at the end. Furthermore, the investigators will ask the participant about the dietary intake and habits.

The aim is to learn how the 24-hour rhythm is connected to the social activity and behavior as well as blood pressure and metabolites as markers for the health status.

Inclusion Criteria:

• Volunteers must be in good health as based on medical history, physical examination, vital signs, and laboratory tests as deemed by PI;
• Volunteers are capable of giving informed consent;
• 25-35 years of age;
• Own a cell phone with internet access (smartphone with Android operating system only at this point) which installs the social sensing application ginger.io;
• Non-smoking;
• Male subjects only if feasible during recruitment; and
• In case female volunteers are invited to enroll: non-pregnant, female subjects must consent to a urine pregnancy test.

Exclusion Criteria:

• Recent travel across time zones (within the past month);
• Planned travel across time zones during the planned study activities;
• Volunteers with irregular work hours, e.g. night shifts.
• Use of illicit drugs;
• Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening.
• Subjects with any abnormal laboratory value or physical finding that according to the investigator may interfere with interpretation of the study results, be indicative of an underlying disease state, or compromise the safety of a potential subject.

Healthy volunteers

1 year

All non serious AE were resolved, Serious AE: None