Naismith’s Rule, or Just How Long Does It Take to Walk a Mile©

 

 

Rough winter terrain, just how long will it take you to walk a mile here?  Photograph by Kathleen Reynolds, used with permission.

I actually started writing this article more than 20 years ago, I just never finished it – Author’s Note

 

Did you ever notice that it takes longer to bushwhack through heavy brush or to stomp through deep snow, than it does to walk alongside a road?  Did you ever wonder how long it takes to walk a mile in the wilderness?

 

The distance, speed and time triangle, graphic by the Author.

A hike or a walk in the wilderness is often measured in the time it takes to cross the distance, rather than in the distance itself.  This is because of all the things that can slow you down in the wilderness, things like rough terrain, climbing up or down hills, brush, heat, snow, sand, mud, or darkness, to name a few.

 

So, just how long does it take to walk a mile, anyways?

 

Well, W. W. Naismith developed a handy rule of thumb to help you to estimate how long it will take you to travel through the wilderness, way back in 1892.¹

 

The first appearance of Naismith’s rule, from Scottish Mountaineering Club Journal, Volume 2, 1893, page 136.

Naismith’s basic rule of thumb states that as a base line time a walker can walk 3 miles (5 km) in an hour along a path, however the walker will incur a time penalty, adding one hour to the base time for every 2,000 feet (600 meters) of ascent that he or she makes. 

 

Now, Naismith was an optimist, and he created his rule of thumb for reasonably fit walker, travelling through typical hill country, in typical weather, along a relatively flat, clear, and level path.  It is important to remember that Naismith’s rule gives a reasonable minimum estimate of the time require to complete a hike.²

 

Refinements, corrections, modifications...they’re everywhere!

 

For many years people have been trying to refine or correct Naismith’s basic rule, so that it gives a more correct estimate of the time needed to complete a walk.  Some people have come up with corrections due to the difficulty of the path or the level of the physical fitness of the walker, others with modifications that correct for steep descents, an issue that Naismith didn’t address, this is important because when ascending or descending a steep slope a person naturally takes shorter steps or they will zigzag up or down the hillside on switchbacks, and this increases the distance traveled while reducing the slope.  R. Aitken, in his 1977 PhD thesis, suggested 3 miles (5 km) of travel per hour could only be achieved on roads or good paths and that on all other ground, the base distance should be reduced to 2-½ miles (4 km) per hour.  Longmuir, in his 1984, book Mountaincraft and Leadership, offered another refinement when he suggested the following time penalties, subtracting 10 minutes from the base time for every 1,000 feet (300 meters) of descent along slopes between 5^o to 12^o, and when descending slopes greater than 12^o, adding 10 minutes to the base time of travel for every 1,000 feet (300 meters) of descent.³  Bob Wirth suggested in Backpacking in the 80’s, as a rule of thumb, that it will take you twice as long to hike up a steep trail as it will to hike back down.  And even the Unites State Army got into the act, writing in Mountain Operation, FM 90-6, (1980), that because of the steeper slopes found in mountainous areas that a time penalty of one hour should be added when ascending 1,000 feet (300 meters) or when descending 2,000 feet (600 meters) of elevation.⁴ 

 

So, which should I use?

 

An excerpt from Wolseley, General Viscount; The Soldier’s Pocket-Book For Field Service, by Wolseley, General Viscount, page 323 to 324.

So, just what corrections, modifications or refinements should you use when planning your route and estimating how long it will take to complete your travels.  Well, do what everyone else has done and add your own modifications, corrections, and refinements to Naismith’s basic rule of thumb.

 

An excerpt from Wolseley, General Viscount; The Soldier’s Pocket-Book For Field Service, by Wolseley, General Viscount, page 323.

It is important to remember that Naismith’s Rule includes a built-in 5 to 10 minute rest break, or halt, every hour to tie shoes, adjust pack straps, drink some water, etc.  Also, if you are low on water, spend your break purifying some more, so that you will have something to drink on your next break.  On hikes longer than 5 hours, add in a 30-minute rest break at the halfway point for lunch, this will help combat the effects of fatigue.

 

Graphic by the Author.

Here are some suggestions for corrections you might like to consider, from various sources⁵, when creating your own modifications to Naismith’s Rule.

  

Base Times

Good path                                       3 mph      or     5 kmph

Rough path                                     2-½ mph  or     4 kmph

Scrambling⁶ up steeps slopes          2 mph      or     3 kmph

Walking through the forest             1-½ mph  or     2 kmph

        without a trail and no

        undergrowth

Bushwhacking through dense         1 mph      or     1-½ kmph

        undergrowth or

rough terrain

* All of these base times assume that you are carrying than a light pack of no more than 40 lbs. (18 kgs)

 

Time Penalties

Walking at night                             Add 20 minutes per hour

 

For every 10 lbs. (4.5 kg) over       Add 10 minutes per hour

        40 lbs. (18 kg) carried

 

When the temperature is                 Add 5 minutes per hour

        between 67^o F – 77^o F

        (19^o C – 25^o C)⁷

 

When the temperature is                 Add 10 minutes per hour

        between 77^o F – 87^o F

        (25^o C – 31^o C)

 

When the temperature is                 Add 20 minutes per hour

        between 87^o F – 97^o F

        (31^o C – 36^o C)

 

For every 5 hours hiked                  Add 1 hour                     

        without a long break,

        due to fatigue

 

You are an inexperienced               Add 10 minutes per hour

or out-of-shape hiker⁸

 

For every 2,000 feet (600 m)          Add 1 hour

of ascent on slopes

between 5^o and 12^o

 

For every 1,000 feet (300 m)          Add 1 hour

ascent on slopes

greater than 12^o

 

For every 1,000 feet (300 m)          Subtract 10 minutes per hour

descent on slopes

between 5^o and 12^o

 

For every 1,000 feet (300 m)          Add 10 minutes per hour

descent on slopes

greater than 12^o

 

Now that you have modified Naismith’s rule of thumb, get out into the wilderness, and test it.  Measure how long it takes you and if you are within 5% of the time you estimated, then you have estimated correctly, if not try some more or different modifications, refinements, and corrections, until you get it right!

 

But what about when I’m not hiking, or in the winter...

 

“But what about when I’m not hiking, what if I am canoeing”, you ask, “And, what if it is in the winter and I am snowshoeing, or cross-country skiing”?

 

Good questions.  Let’s talk about them.  Oh, and by the way whenever you are on foot, winter, spring, summer or fall, the earlier modifiers for hiking apply, so if you are wearing a 60-pound (27 kg) pack, are climbing or descending in elevation, whether you are tramping over a portage, or walking across a snowy field, remember that the earlier time penalties still apply.

 

When canoeing, allow for the following travel rates.

   

Base Times

Open lakes with no portages          3 mph      or     5 kmph

Mixed lakes and portages               2 mph      or     3 kmph

Portages                                          1 mph      or     1-½ kmph

Creeks and winding rivers              1 mph      or     1-½ kmph

 

Time Penalties

For every 5 hours canoed               Add 1hour                      

        without a long break,

        due to fatigue

Portaging on a poorly                     Add 10 minutes per hour

        maintained portage

Portaging on an unmaintained        Add 20 minutes per hour

        portage

 

Inexperienced or out-of-shape        Add 10 minutes per hour

canoers

 

And don’t forget, that multiple trips over the same portage doesn’t just double the distance and time it triples it!  For more see “Algonquin Portaging 101 ©”, HERE.

 

The effect of multiple trips over the same portage on time and distance, graphic by the Author.

During the winter, the depth of the snow can seriously affect the time it takes to cover a distance.  And wearing snowshoes or cross-country skis, while they keep you from sinking in the snow, can change the base rate of travel.  The Basic Cold Weather Manual, FM 31-70, from 1968, covers this very well.

 

Basic Cold Weather Manual, FM 31-70, page 61

Some other things to remember

 

Photograph by the Author.

According to Bob Wirth’s Backpacking in the 80’s, you should allow one hour of daylight for waking up, cooking breakfast and breaking camp and one to two hours for setting up camp and cooking dinner.  During the winter, in the northern hemisphere, you only have about six to seven hours of daylight and during the summer you will have between nine and eleven hours of sun light – so plan accordingly.

 

Don’t forget to come back next week and read “The Top Ten Wilderness Survival Skills...Number Eleven©”, where we will talk about all the survival skills that didn’t fit into my top ten list.

 

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at BandanaMan Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

 

That is all for now, and as always, until next time, Happy Trails!

 

 

Notes

 

¹ William Wilson Naismith was born near Glasgow, Scotland in 1856.  He worked in insurance his whole life; however, he is best known as a mountaineer, rock climber, skier, and meteorologists.  In 1899, he helped to create the Scottish Mountaineering Club.  He died in 1935, at the age of 79.

 

From “It's Time To Head For The Hills”, by Toby Shergold.

 

² “Modelling Naismith’s Rule”, Steffen Fritz and Steve Carver.

 

³ Ibid.

 

⁴

 

An excerpt from Mountain Operations, FM 90-6, by the Department of the Army.

The steepness or degree of a slope is vague or arbitrary classification that is often arbitrary, with little agreement between experts.  However, the U.S. Geological Survey defines gentle slopes as slopes which are less than 15%, moderate slopes, which are somewhat more difficult to climb or descend, as slopes from 15% to 50% (or 8-½^o to 26-½^o), and steep slopes, to be slopes greater than 50% (or almost 30^o) up to 100%, (or 45^o).  These last slopes are difficult to climb and often must be crossed by scrambling up or down using your hands. 

The greater the slope, the greater the difficulty in ascending or descending the hill or mountainside. 

 

As page 1-3 of Mountain Operations notes, in mountainous areas, which are landforms where the local relief or distance from the valley floor to the summit is greater than 1,000 ft (300 meters) and in hill country where the local relief is less than 1,000 feet (300 meters) more than 50% of the slopes that you will encounter will be moderate to steep slopes greater than 15% or 8-½^o.  The more mountainous the area, the steeper the slopes are likely to be.

 

An excerpt from Hillside Materials and Slopes of the San Francisco Bay Region, California, Stephen D. Ellen, and Carl M. Wentworth.

As a steepness comparison, correct slope for a ladder is a 4:1 ratio, or a slope of approximately 75^o.

 

From Mountain Operations, FM 90-6, by the Department of The Army, Hillside Materials and Slopes of the San Francisco Bay Region, California, by Stephen D. Ellen, and Carl M. Wentworth, and Final Environmental Impact Statement, Proposed Southern California Lease Offering April, 1984, Department of the Interior.

 

⁵ From Winter Wise, Travel and Survival in Ice and Snow, by Montague Alford; Mountain Operations, FM 90-6, June 30, 1980, by the Department of the Army; “Modelling Naismith’s Rule”, by Fritz Steffen, and Steve Carver; Backpacking in the 80’s, by Bob Wirth; The Soldier’s Pocket-Book For Field Service, by General Viscount Wolseley, and “The Art of Navigation”, (unfortunately this website is no longer available).

 

⁶ Scrambling has been defined by some as hiking that requires the use of hands, but not ropes.  It is a vague term to describe an activity that lies somewhere between hiking, easy mountaineering, and rock climbing.

 

⁷ The Soldier’s Pocket-Book For Field Service, by General Viscount Wolseley

 

⁸ According to “The Art of Navigation”, which unfortunately is no longer available, very fit, and experienced hikers can reduce the total time traveled by ¹/₃.

 

 

Sources

 

Alford, Montague; Winter Wise, Travel and Survival in Ice and Snow, [Heritage House Publishing Company Ltd., Surrey, B.C., 1999], page 49

 

Department of the Army, Basic Cold Weather Manual, FM 31-70, April 12, 1968, [Paladin Press, Boulder, CO, 1974], page 61

 

Department of the Army, Mountain Operations, FM 90-6, June 30, 1980, [Washington, DC, June 30, 1980], page 1-3

 

Douglas, William, Editor; Scottish Mountaineering Club Journal, Volume 2, [The Scottish Mountaineering Club, Edinburgh, 1893], page 136, https://books.google.com/books?id=-hn0Xst3g_gC&pg=PA136&dq=%22this+tallies+exactly+with+a+simple+formula%22&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwie2PqqxqP2AhVPonIEHUpHCpMQ6AF6BAgLEAI#v=onepage&q=%22this%20tallies%20exactly%20with%20a%20simple%20formula%22&f=false, accessed February 28, 2022

 

Ellen, Stephen D. and Wentworth, Carl M.; Hillside Materials and Slopes of the San Francisco Bay Region, California, U.S. Geological Survey, Professional Paper 1357, [United State Government Printing Office, Washington, D.C., 1995], page 13 to 14, https://books.google.com/books?id=mBuac6RrOJMC&pg=PA14&dq=slope+%25+steep+gentle&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwiAv6u9n6b2AhUzp3IEHaz2DMwQ6AF6BAgDEAI#v=onepage&q=slope%20%25%20steep%20gentle&f=false, accessed March 1, 2022

 

Fritz, Steffen, and Carver, Steve; “Modelling Naismith’s Rule” School of Geography, University of Leeds, http://www.geog.leeds.ac.uk/papers/98-7/, accessed February 28, 2022

 

Shergold, Toby, “It's Time To Head For The Hills”, The Independent, March 29, 2003, https://www.independent.co.uk/travel/news-and-advice/it-s-time-to-head-for-the-hills-5352619.html, accessed February 28, 2022

 

Wirth, Bob; Backpacking in the 80’s, [Parker Publishing Company, Inc. West Nyack, NY, 1984], page 147-149

 

Wolseley, General Viscount; The Soldier’s Pocket-Book For Field Service, [MacMillan and Co, London, 1886], page 323 to 324, https://books.google.com/books?id=uz9FAAAAYAAJ&printsec=frontcover&dq=the+soldier%27s+pocket-book+for+Field+Services+1886&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwj-4MvIsJ72AhU8knIEHfQnB3MQ6AF6BAgJEAI#v=onepage&q=the%20soldier's%20pocket-book%20for%20Field%20Services%201886&f=false, accessed February 26, 2022.