Rucking with Heavy Loads Can Make Your Mood Feel Worse. How to Use This to Your Advantage.
- Alastair Hunt
- 2 days ago
- 4 min read
Updated: 18 hours ago
Most of us know that exercise generally improves mood. Go for a jog, lift some weights, take a brisk walk, and you will likely feel better afterward. But what happens when you strap on a heavy pack and walk for two hours straight, with no option to slow down or stop? A study set out to answer exactly that question, with findings that are worth paying attention to if you do any kind of loaded walking, hiking, or rucking.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies / resources at bottom of page.
What the Study Did
Researchers recruited 13 active-duty soldiers and had each of them complete two separate two-hour treadmill marches on different days: one unloaded (just an empty rucksack weighing around 3.8kg) and one carrying up to 50% of their own body weight. That is a substantial load. For a 80kg person, that means 40kg on their back.
Every 40 minutes during the march, participants rated how they felt physically and emotionally, using validated scales measuring perceived effort, emotional pleasure or displeasure, and arousal. Additional mood and anxiety questionnaires were completed before and after each session to capture how feelings changed from start to finish.
What They Found
The loaded march reliably made soldiers feel worse, emotionally. Feelings became more negative and less positive as the march progressed, and anxiety levels were significantly higher in the loaded condition overall compared to the unloaded march. Perceived exertion, heart rate, and oxygen demand were all substantially elevated when carrying weight.
What makes this finding particularly interesting is that the emotional decline happened even though physiological measures remained in what exercise scientists classify as the moderate-intensity range.
Standard models of exercise and emotion, particularly a framework called Dual Mode Theory, predict that moderate-intensity exercise should feel reasonably pleasant. Load carriage broke that rule. The researchers suggest this is because carrying heavy weight introduces a layer of physical discomfort, including back pain and musculoskeletal strain, that ordinary cardiovascular effort does not. Your body is working hard and hurting at the same time, and that combination shifts emotional experience in a way that heart rate and oxygen consumption alone do not capture.
The study also found a meaningful relationship between physiological fatigue markers and emotional state. Higher heart rate and oxygen consumption at certain points in the march were associated with more negative emotions and higher perceived exertion. In other words, how hard your body is working and how bad you feel are closely linked during loaded marching. Importantly, earlier research (Hartman et al) has shown that the rate at which your mood declines during exercise may signal how close you are to the point of giving up entirely.
Your feelings, it turns out, may be an early warning system for impending fatigue, appearing before your legs or lungs send the same message.
If you are training for the PARAS'10, a Norwegian Foot March, or just to get fast and fit, our self-paced online course"Built to Ruck The Science and Practice of Rucking" covers everything the research tells us about load carriage training, pacing, progression, heat management, hydration, fueling and more. It is built for ruckers at every level of experience, and draws directly on the peer-reviewed military and sports science research.
What This Means for Us
If you ruck, hike with a loaded pack, or train for ruckomng events, expect your mood to dip as the effort accumulates, and expect it to dip more steeply than it would on an equivalent unloaded walk. This is normal, predictable, and physiological rather than a reflection of your mental toughness or readiness.
Understanding that the emotional grind is a built-in feature of loaded marching, rather than a personal failing or a sign that something is wrong, may help you push through it more effectively. Reframing low mood mid-march as a normal physiological response rather than a warning to stop can be a genuinely useful mental tool.
The findings also suggest that paying attention to how you feel during training, not just your pace, heart rate, or distance covered, could give you valuable information. A steeper or faster-than-usual emotional decline on a familiar route might indicate you are closer to your limit than the numbers on your watch suggest. Mood, in this sense, is data worth tracking.
One practical caveat: this was a small study of 13 soldiers, conducted on a treadmill rather than outdoors, and the findings may not translate perfectly to every type of loaded exercise. But the direction of the results is consistent with what most experienced ruckers already know in their gut. Heavy loads feel hard in ways that go beyond the purely physical.
Wherever you are: train safe and enjoy the process!
Alastair
Read about physical durability here.
Key Studies
Giles GE, Grandjean DA Costa K, Olenich SA, Powell KJ, Hart-Pomerantz H, Adelman MJ, Elmore WR, Cantelon JA. Load Carriage and Physical Exertion Influence Soldier Emotional Responses. Med Sci Sports Exerc. 2022 Dec 1;54(12):2149-2157. doi: 10.1249/MSS.0000000000002997. Epub 2022 Sep 27. PMID: 36377052.
Hartman ME, Ekkekakis P, Dicks ND, Pettitt RW. Dynamics of pleasure-displeasure at the limit of exercise tolerance: conceptualizing the sense of exertional physical fatigue as an affective response. J Exp Biol. 2019 Feb 4;222(Pt 3):jeb186585. doi: 10.1242/jeb.186585. PMID: 30559299.
Other
Armstrong NC, Smith SJR, Risius D, Doyle D, Wardle SL, Greeves JP, House JR, Tipton M, Lomax M. Cognitive performance of military men and women during prolonged load carriage. BMJ Mil Health. 2023 Feb;169(1):37-45. doi: 10.1136/bmjmilitary-2021-002000. Epub 2022 Apr 7. PMID: 35393357; PMCID: PMC9887367.
Martin K, Périard J, Rattray B, Pyne DB. Physiological Factors Which Influence Cognitive Performance in Military Personnel. Hum Factors. 2020 Feb;62(1):93-123. doi: 10.1177/0018720819841757. Epub 2019 Apr 22. PMID: 31009241.
Eddy MD, Hasselquist L, Giles G, Hayes JF, Howe J, Rourke J, Coyne M, O'Donovan M, Batty J, Brunyé TT, Mahoney CR. The Effects of Load Carriage and Physical Fatigue on Cognitive Performance. PLoS One. 2015 Jul 8;10(7):e0130817. doi: 10.1371/journal.pone.0130817. PMID: 26154515; PMCID: PMC4496096.
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