Importance of NEAT

The importance of obesity to world health is without question. There are 1 billion people in the world who are overweight and 300 million with obesity. In USA, data from two NHANES surveys show that among adults aged 20-74 years, the prevalence of obesity increased from 15.0% (in the 1976-1980 survey) to 32.9% (in the 2003-2004 survey). The health consequences of obesity are dire. It could lead to type II diabetes, heart disease, and even some types of cancers.

Recent work suggests that this is driven by a reduction in energy expenditure, rather than a rise in energy intake. In Britain where obesity has doubled since the 1980's, energy intake appears to have decreased on average. Two major components of energy expenditure are Exercise Activity Thermogenesis and Non-Exercise Activity Thermogenesis (NEAT). NEAT is the most variant portion of energy expenditure, and likely, the culprit behind the obesity epidemic.

NEAT, according to research conducted by Dr. James Levine of Mayo Clinic, is the energy expenditure of all physical activities other than volitional sporting-like exercise. It includes all the activities that render us vibrant, unique, and independent beings such as working, playing, and dancing. Contrary to conventional wisdom, NEAT activities expend a significant amount of energy (Figure 1).

NEAT reduction is the result of evolving from the hunting/agriculturalist/industrial into a service oriented society where computer work at the office is the norm and TV watching/video gaming the most widespread form of entertainment.

Figure1:

Left: NEAT activities have higher energy expenditure than intuitively expected.

Right: Obese people spend more time in sitting than lean people.

 

NEAT-o-Games

The ultimate goal of this research is to increase NEAT in the modern lifestyle. The most difficult and important part is how to motivate people to change something as fundamental as their everyday habits. Sedentariness is almost addictive and is reinforced by the specifications of the modern work and leisure environments. An important consideration here is that NEAT is omnipresent in our life (or should be anyway), in contrast to volitional sporting activities, which are bound to specific locations and times. Therefore, strong motivation and ubiquity are two key issues. We address the former by opting for games - that is, a successful form of entertainment throughout human history, which may be a potent motivator. We address the latter, by opting for a game design that does not require the full attention of the user all the time and is implemented using wearable gadgets, that is, accelerometers and cell phones.

The so-called NEAT-o-Games are envisioned as a collection of cell phone games where `activity points' may be earned and consumed across the game space. We implemented two games so far, the NEAT-o-Race and NEAT-o-Sudoku game.

 

System Architecture

We use a tri-axial accelerometer to measure physical activity. The form factor of the sensor is similar to a mobile phone and is typically attached to the waist of the user (see Figure). It communicates with a Palm Treo 700w/wx phone through a Bluetooth connection. Measurements are recorded four times every second and are correlates of the energy expended by the user due to motion at the time.

Figure2: Player wears activity sensor at his waist and holds a Palm Treo PDA at his palm. The devices are indexed in the right panel.

Concurrently, these data are transmitted to an SQL Server database through cellular broadband or Wi-Fi. Thus, the systems of other NEAT-o-Games players (anywhere in the world) can access these data and make competitive real-time racing possible.

 

Design Principles

The NEAT-o-Games design is based on the following principles (see Figure):

Figure3: NEAT-o-Games design principles as exemplified by characteristic screen shots

 

Accelerometer

We created a light weight accelerometer sensor package that can be mounted almost anywhere on the body (foot, leg, arm, or waist). It is comprised of a microcontroller, sensor, and communication device that allows for a remote, wireless connection to be established between itself and any Bluetooth enabled device (see Figure). It is driven by a rechargeable Lithium Polymer (Li-Poly) battery that lasts up to 7 hours when the device is active and transmission of data is continuous at 4 times/sec (default rate).

The accelerometer reading approximates better the aerobic activity of the player when it is placed on his/her waist, as it is closer to the mass center of the human body.

Figure4: Our telemetry device, which consists of accelerometer, microcontroller, and transmitter. Battery is attached to the rear side of the board. Dimensions are 5.1 cm x 4.2 cm x 2.0 cm.

 

Database and Network Connectivity

We use a relational database instance of SQL Server 2005 to store player information and his/her activity record. This is the central hub of the system where all information is stored and post-processed. One typical problem in cell phone based systems is intermittent network failure. Even if the player is living in an urban place where coverage is strong, intermittent network failure is still unavoidable (e.g., the player goes into an underground library floor). When network connection is down, NEAT-o-Games store the player's activity record to a local file system, which acts like a cache and is flushed to the server database after the network connection is back. At the same time, it automatically tries to reconnect to the network so that the player does not have to engage in any restorative action. The cache is transmitted in packets at opportune times, in order to avoid any disruption to the normal cell phone operation. This way, NEAT-o-Games manage intermittent network failures in a manner highly transparent to the player. Even when NEAT-o-Games are run in background mode, they use occasional messaging to inform players about major events in the race. For example, they send an alert to the player when the opponent has built too much of a lead in the race (see Figure 5). In the contrary situation that finds the player far ahead in the race, a congratulatory message notifies the player to this effect.

Figure 5: Messaging when NEAT-o-Games are run in background mode. Left screen shows a rallying message that alerts the player who is left behind. After pressing 'ok', the NEAT-o-Games home screen will be restored. Right screen shows a congratulatory message to the winner of the race in the previous day.

 

 

Acknowledgements

The NEAT-o-Games project is supported by the Eckhard-Pfeiffer Endowed Chair Fund of Dr. Ioannis Pavlidis at UH and NSF grant IIS-0414754.