Mens Tank Sleep Set

Alejandro is wearing a size medium and measures 6’.

Mens Tank Sleep Set

Sleep Tank
Sleep Short
Size Guide

Upgrade your birthday suit

While it’s arguably the sexiest of all options, sleeping naked isn’t the smartest way to sleep. The layer closest to the skin regulates body temperature and moves sweat away from the body—so if that’s your favorite old T-shirt or even if it’s a high-thread-count cotton sheet, it won’t protect from night sweats. By releasing 100% of your body heat, the CoolLife Sleep Set continuously cools your body throughout the night to give you the best rest possible. The tank and short combination is ideal for sleepers who prefer a little skin contact, and doubles as performance wear in a pinch. 

According to scientists, to fall and stay asleep, the body’s core temperature needs to drop by 1°C, or 2° to 3°F. This process induces sleep more quickly, and increases deep sleep by 10–20% (that’s the non-REM, slow-wave sleep in which brain waves slow dramatically and your body heals physically, recovers from illness, and deals with stress). Our CoolLife Sleep tech continuously cools your body by 1.8C/3.3F (19%) more than Dagsmejan Nattcool Sleep Tech T-shirt, thermoregulating your temperature throughout the night to deliver deep sleep, which is the very basis of wellness in waking life. 

Save 10% when you buy as a set.



Sustainability Index

We make every effort to reduce this product’s impact on the earth. 

Learn More
Global Warming Potential

47% fewer CO2 emissions

Water Pollution

74% less water pollution

Water Use

74% less water usage

Fossil Fuel Depletion

26% less fossil fuel depletion

Chemical Impact

60% reduced chemical impact

Earth Friendly Materials

Constructed with 39% recycled materials by fabric weight.

We use 100% recycled polyester labels and sewing thread.

Sustainable Packaging

We reduce our environmental footprint by choosing our packaging wisely. That means no hangtags or swift tacks and no conventional plastic. When we do use packaging, we choose 100% compostable alternatives made from the bio-based polymer PBAT and the plant-based polymer PLA. 


Compared to products that use Lyocell. Based on Higg MSI 3.3 data at Percentage reductions pertain to the finished material phase.


CLO Rating

  1. The standard measurement of how warm a textile keeps you (the higher the CLO, the warmer you are).
  2. The degree of insulation provided by an article of clothing. 
  3. LifeLabs CLO levels are significantly higher than materials almost 30% heavier. 

Infrared Radiation

  1. A type of electromagnetic radiation produced when atoms absorb and then release energy with a frequency lower
than visible light.
  2. Thermal energy your body is producing all the time. 


  1. The measure of an object's ability to emit infrared energy (heat by radiation).
  2. A low-emissivity material (like aluminum) acts as a radiant barrier and decreases 
the amount of infrared radiant heat
 that escapes. 

Higg Index

  1. A tool for the apparel and footwear industry to assess the environmental impacts of raw materials and the lifecycle impacts of products.
  2. The industry-leading value chain measurement methodology developed by the Sustainable Apparel Coalition.


  1. A regular organic or inorganic framework supporting a porous structure.
  2. A nano-scale cell structure that allows body heat to escape through pores to maximize comfort.


  1. Perfluorinated chemicals, or a subset of perfluorinated chemicals called perfluorocarbons are traditionally used in textile manufacturing to provide water repellency.
  2. LLD uses PFC-free water repellent finishes to lower or impact on the environment and human health.


  1. Large molecules made by bonding (chemically linking) a series of building blocks.
  2. Polymers are chains of chemically bonded atoms.


  1. A material that conducts infrared heat away from your skin at a higher, more efficient rate.
  2. Polyethylene has a low Materials Sustainability Index rating compared to conventional synthetic fibers used in apparel today.

QMax Index

  1. Measurement of thermal transport.
  2. A higher Qmax value indicates a faster tranfer of heat from the body to the fabric surface, resulting in a cooling effect.
  3. A measure of predicting the warm/cool feeling of fabrics.  


  1. The return of light, sound or heat from a surface.
  2. A reflective fabric or material reflects the body's heat back to itself.


  1. A type of homeostasis and a means of preserving a stable internal temperature in order to survive.
  2. Thermoregulation is the maintenance of a relatively constant core body temperature.


  1. Allowing the passage of a specified form of radiation.
  2. Honest and open; without secrets or deceit. Transparency in materials means that the textile barrier blocks natural elements (like rain and sunlight) and allows other to pass through (like persperation and body heat.)

Sizing & Fit

CoolLife Sleep Tank XS S M L XL XXL
Body Length 25 3/4 26 1/4 26 3/4 27 1/4 27 3/4 27 3/4
Chest 34 36 1/2 39 42 46 49


CoolLife Sleep Short XS S M L XL XXL
Waist 22 1/2 25 1/2 28 30 1/2 35 38
Inseam 6 1/2 6 3/4 7 7 1/4 7 1/2 7 1/2


CoolLife Sleep Tank XS S M L XL XXL
Body Length 65.4 66.7 67.9 69.2 70.5 70.5
Chest 86.4 92.8 99 106.6 116.8 124.4


CoolLife Sleep Short XS S M L XL XXL
Waist 58.4 64.8 71.2 78.8 89 96.6
Inseam 16.5 17.1 17.8 18.4 19.1 19.1