Activate America
A Hot Topic for Outdoor Activities
Spring and summer temperatures usually move individuals outdoors for recreational and exercise activities. The past spring season was perfect for outdoor activity participation but did little in providing individuals the opportunity to get acclimated to higher temperatures and humidity, especially when those temperatures appear very abruptly.
Understanding heat and it’s affects on the body during outdoor exercise and activity is important for the continuation and enjoyment of those activities without developing the negative side effects of heat cramps, heat exhaustion or heat stroke. Heat cramps are usually associated with excessive sweating during exercise and are caused by the loss of salt during sweating. Heat exhaustion occurs when the body’s ability to sweat is overwhelmed leading to an increase in the core body temperature. Heat exhaustion symptoms can include: skin that is pale, cool and clammy, dizziness, weakness and disorientation. If not identified, heat exhaustion can lead into heat stroke which can be potentially life threatening. An individual suffering from heat stroke will have flushed skin, minimal or no sweating, skin that is hot to the touch, appear confused and may faint.
Whether you are a novice or experience outdoor enthusiast, your body needs time to adjust to the higher temperatures. According to the American College of Sports Medicine, it takes about 14 days to get acclimated to higher temperatures and humidity. During this time, outdoor activities and exercise should be continued but with special attention to strategies that prevent heat related illnesses.
Drinking fluids and keeping hydrated is number one when participating in outdoor activities in hot and humid weather. By maintaining body fluids an individual can maintain the ability to sweat and therefore keep proper body temperatures. Sweating is the body’s mechanism for dispelling heat. If an individual becomes dehydrated they loose this mechanism resulting in higher core temperatures. It’s best to consume fluids such as water, sports drinks or fruit juices instead of caffeinated or alcoholic choices. Try to consume more than is necessary and do not wait until thirsty. The recommended fluid intake is 20 oz. two to three hours before the activity; 10 oz. for every ten to 20 minutes during the activity; and 20 oz. after.
Additionally, an individual can reduce the effects of heat by: reducing the exercise or activity intensity, wearing loose fitting, light colored clothing, wearing a hat, exercising in the morning or late evening when the temperatures are cooler, wearing sunscreen to protect from sunburn, and paying attention to the heat stress index which indicates the risk of heat injury based on the combination of air temperature, relative humidity and air quality. ( See Chart)
By paying attention to your body’s needs and using these strategies to beat the heat, individuals can continue to exercise and enjoy outdoor recreational activities and sports when the heat is on.
The Heat Index
The heat index (see chart below) is the "feels like", or apparent, temperature. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration.
As the heat index rises, so do health risks. When the heat index is 90°-105°F, heat exhaustion is possible. When it is above 105°F, it is probable. Heatstroke is possible when the heat index is above 105°F, and very likely when it is 130°F and above. Physical activity and prolonged exposure to the heat increase the risks.
Heat exhaustion occurs when the body is dehydrated.
- Symptoms: headache, nausea, dizziness, cool and clammy skin, pale face, cramps, weakness, profuse perspiration
- First aid: move to a cooler spot, drink water with a small amount of salt added (one teaspoon per quart)
- It can lead to collapse and heatstroke.
Heatstroke occurs when perspiration cannot occur and the body overheats.
- Symptoms: headache, nausea, face flushed, hot and dry skin, no perspiration, body temperature over 101°F, chills, rapid pulse
- First aid: cool person immediately, move to shade or indoors, wrap in a cool, wet sheet, get medical assistance
- It can lead to confusion, coma, and death.
The following chart shows the health risks as temperature and relative humidity rise.
|
The Heat Index
|
|
Air
Temp
(°F)
|
Relative Humidity (percentage)
|
|
|
0
|
5
|
10
|
15
|
20
|
25
|
30
|
35
|
40
|
45
|
50
|
55
|
60
|
65
|
70
|
75
|
80
|
85
|
90
|
95
|
100
|
|
|
135°
|
120
|
126
|
|
|
|
130°
|
117
|
122
|
131
|
|
|
|
125°
|
111
|
116
|
123
|
131
|
141
|
|
|
|
120°
|
107
|
111
|
116
|
123
|
130
|
139
|
148
|
|
|
|
115°
|
105
|
107
|
111
|
115
|
120
|
127
|
135
|
143
|
151
|
|
|
|
110°
|
99
|
102
|
105
|
108
|
112
|
117
|
123
|
130
|
137
|
143
|
150
|
|
|
|
105°
|
95
|
97
|
100
|
102
|
105
|
109
|
113
|
118
|
123
|
129
|
135
|
142
|
149
|
|
|
|
100°
|
91
|
93
|
95
|
97
|
99
|
101
|
104
|
107
|
110
|
115
|
120
|
126
|
132
|
138
|
144
|
150
|
|
|
|
95°
|
87
|
88
|
90
|
91
|
93
|
94
|
96
|
98
|
101
|
104
|
107
|
110
|
114
|
119
|
124
|
130
|
136
|
140
|
150
|
|
|
|
90°
|
83
|
84
|
85
|
86
|
87
|
88
|
90
|
91
|
93
|
95
|
96
|
98
|
100
|
102
|
106
|
109
|
113
|
117
|
122
|
126
|
131
|
|
|
85°
|
78
|
79
|
80
|
81
|
82
|
83
|
84
|
85
|
86
|
87
|
88
|
89
|
90
|
91
|
93
|
95
|
97
|
99
|
102
|
105
|
108
|
|
|
80°
|
73
|
74
|
75
|
76
|
77
|
77
|
78
|
79
|
79
|
80
|
81
|
81
|
82
|
83
|
84
|
85
|
86
|
87
|
88
|
89
|
90
|
|
|
75°
|
69
|
69
|
70
|
71
|
72
|
72
|
73
|
73
|
74
|
74
|
75
|
75
|
76
|
76
|
77
|
77
|
78
|
78
|
79
|
79
|
80
|
|
|
70°
|
64
|
64
|
65
|
65
|
66
|
66
|
67
|
67
|
68
|
68
|
69
|
69
|
70
|
70
|
70
|
70
|
71
|
71
|
71
|
71
|
72
|
|
|
|
=
|
Heatstroke risk extremely high
|
|
|
=
|
Heat exhaustion possible
|
|
|
=
|
Heat exhaustion likely, heatstroke possible
|
|
|
=
|
Fatigue possible
|
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