Work/Rest Times and Fluid Replacement Guide
Heat
Category

WBGT
Index
(ºF)

Easy Work
Walking on hard surface, 2.5
mph, <30 lb. load; weapon
maintenance, marksmanship
training.
(minutes)

Fluid
Intake

Work/Rest

(quarts/hour)

78º - 81.9º

NL

2

82º - 84.9º

(green)
3

85º - 87.9º

(yellow)
4

(red)
5

(black)

(minutes)

Work/Rest

(quarts/hour)

½

NL

¾

40/20
(70)*

¾ (1)*

NL

½

50/10
(150)*

¾ (1)*

30/30
(65)*

1 (1¼)*

NL

¾

40/20
(100)*

¾ (1)*

30/30
(55)*

1 (1¼)*

¾ (1¼)*

20/40
(50)*

1 (1¼)*

1 (1¼)*

10/50
(45)*

1 (1½)*

88º - 89.9º

NL

¾

30/30
(80)*

> 90º

50/10
(180)*

1

20/40
(70)*

NL = No limit to work time per hour.

Approved for public release,
distribution unlimited.
CP-O33-0615

Hard Work
Walking in sand, 2.5 mph, with
load; field assaults.

Fluid
Intake

Work/Rest
1

Moderate Work
Patrolling, walking in sand, 2.5
mph, no load; calisthenics.

(minutes)

Fluid
Intake

(quarts/hour)

*Use the amounts in parentheses for continuous work
when rest breaks are not possible. Leaders should
ensure several hours of rest and rehydration time after
continuous work.

This guidance will
sustain performance
and hydration for at
least 4 hours of work
in the specified heat
category. Fluid needs
can vary based on
individual differences
(± ¼ qt/hr) and
exposure to full sun or
full shade (± ¼ qt/hr).
Rest means minimal
physical activity (sitting
or standing) in the
shade if possible.
Body Armor - Add
5°F to WBGT index in
humid climates.
NBC (MOPP 4) - Add
10°F (Easy Work) or
20°F (Moderate or
Hard Work) to WBGT
Index.
CAUTION: Hourly
fluid intake should not
exceed 1½ qts. Daily
fluid intake should not
exceed 12 qts.